The amount of Thorium-228 left after 22.8 years of decay from an initial 50 gram sample, given its half-life of 1.9 years, is 0.124 grams.
Explanation:In this problem of thorium -228 decay, we apply the formula for exponential decay which is A=A0e^-kt. 'A0' represents the initial amount, which in this case is 50 grams. 'A' is the final amount after 't' years, and 'k' is the decay constant. To find the decay constant first, we note that thorium-228 decays to 50% of its initial quantity in 1.9 years. Therefore, we can write the equation 0.5=A0e^-1.9k. Solving for 'k', we get k = ln(2)/1.9, which allows us to derive the time constant for the decay.
Now we use this value of 'k' to find out the amount of thorium-228 left after 22.8 years. Plugging the values into our formula, we get: A = 50e^((ln2/1.9)*-22.8). Solving this yields a value of 0.124 grams, which means option C is correct.
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To find the amount of thorium-228 remaining after 22.8 years, we can use the formula A = A0e -kt. The correct answer is B) 30.32 grams.
Explanation:To solve this problem, we can use the formula A = A0e-kt where A is the amount of the substance at a given time, A0 is the initial amount, k is the decay constant, and t is the time elapsed.
In this case, we are given that thorium-228 decays 50% every 1.9 years.
This means that the decay constant k = ln(2)/1.9. We can substitute the values into the formula and solve for A: A = 50 * e(-ln(2)/1.9)*22.8 = 30.32 grams.
Therefore, the correct answer is B) 30.32 grams.
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When Joe got out of bed, it was 58 in his room. He turned on the heater, and the temperature warmed up to 67 in five minutes. How many degrees per minute did the temperature rise?
Answer: 1.8
Step-by-step explanation:
Answer:
1.8
Step-by-step explanation:
(67 degrees - 58 degrees) / 5 minutes
1.8 degrees per minute
which equation can you use to solve for x
As for a specific equation, I could not say. However, I can tell you how to find x!
The first thing to remember is that a straight line has a 180 degree angle.
You see on the bottom side that we have a 146 degree angle. Now look at the top side. Look closely, and you will see that the two sides are actually identical!
Don't see it? Look at the line on top between x and 56, and imagine it is not there. You see that we actually have the same 146 degree angle, just flipped right side up!
However, this angle does not say 146, but makes an extra line between them with x and 56. This means that x + 56 equals 146!
So we can find x by subtracting 56, from 146, which is... 90!
What is the amplitude, period, and phase shift of f(x) = −4 sin(2x + π) − 5?
Amplitude = −4; period = 2π; phase shift: x = -pie/2
Amplitude = −4; period = π; phase shift: x = pie/2
Amplitude = 4; period = π; phase shift: x = -pie/2
Amplitude = 4; period = 2π; phase shift: x = pie/2
Answer:
Amplitude = -4; period = π; phase shift: x = π/2
Step-by-step explanation:
* Lets revise the trigonometry translation
- If the equation is y = A sin (B(x + C)) + D
* A is the amplitude
- The amplitude is the height from highest to lowest points and
divide the answer by 2
* The period is 2π/B
- The period is the distance from one peak to the next peak
* C is the horizontal shift (phase shift)
- The horizontal shift is how far the function is shifted to left
(C is positive) or to right (C is negative) from the original position.
* D is the vertical shift
- The vertical shift is how far the function is shifted vertically up
(D is positive) or down (D is negative) from the original position.
* Now lets solve the problem
∵ f(x) = A sin (B(x + C)) + D
∵ f(x) = -4 sin (2x + π) - 5 ⇒ take 2 from the bract (2x + π) common factor
∴ f(x) = -4 sin 2(x + π/2) - 5
∴ A = 4 , B = 2 , C = π/2 , D = -5
∵ A is the amplitude
∴ The amplitude is -4
∵ The period is 2π/B
∴ The period = 2π/2 = π
∵ C is the horizontal shift (phase shift)
∴ The phase shift π/2 (to the left)
* Amplitude = -4; period = π; phase shift: x = π/2
The amplitude of the function f(x) = −4 sin(2x + π) − 5 is 4, its period is π, and it has a phase shift of x = -π/2.
Explanation:The amplitude of a trigonometric function like f(x) = −4 sin(2x + π) − 5 is the coefficient in front of the sine function which determines the maximum and minimum value of the function's graph. In this case, the amplitude is the absolute value of -4, which is 4.
The period of the function is found by taking 2π divided by the coefficient of x inside the sine function, which is 2 in this case, yielding a period of π.
The phase shift of the function is determined by solving the equation 2x + π = 0 for x, which gives us a phase shift of x = -π/2. Therefore, the correct description is amplitude of 4, a period of π, and a phase shift of x = -π/2.
Really need help with this!!!
Answer:
Principal Amount= $500
Formula for compound interest:
[tex]A = p (1 + \frac{r}{n} )^{nt}[/tex]
Formula for simple interest:
A = p(1 + r(t) )
There is a mound of g pounds of gravel in a quarry. Throughout the day, 400 pounds of gravel are added to the mound. Two orders of 900 pounds are sold and the gravel is removed from the mound. At the end of the day, the mound has 1,500 pounds of gravel. Write the equation that best describes the situation.
Answer:
The equation that best describes the situation is:
[tex]g +400 -1800 = 1,500[/tex]
Step-by-step explanation:
The initial amount of gravel is g.
[tex]g[/tex]
Then we know that 400 pounds are added
[tex]g +400[/tex]
Two orders of 900 pounds are sold and the gravel is removed from the mound. This is:
[tex]g +400 -2 * 900[/tex]
[tex]g +400 -1800[/tex]
At the end of the day, the mound has 1,500 pounds of serious. This is:
[tex]g +400 -1800 = 1,500[/tex]
The equation that best describes the situation is:
[tex]g +400 -1800 = 1,500[/tex]
And
[tex]g= 1500 +1800 - 400\\\\g=2900[/tex]
The equation that best describes the given situation is[tex]\rm g + 400 - (2\times 900) = 1500[/tex] and this can be determined by forming the linear equation with the help of given data.
Given :
Throughout the day, 400 pounds of gravel are added to the mound.Two orders of 900 pounds are sold and the gravel is removed from the mound.At the end of the day, the mound has 1,500 pounds of gravel.Let the initial amount of gravel be 'g'. Then after the addition of 400 pounds of gravel, the total gravel becomes:
= g + 400
Given that two orders of 900 pounds are sold and the gravel is removed from the mound so, the total gravel now becomes:
[tex]\rm = g + 400 - (2\times 900)[/tex]
= g + 400 - 1800
= g - 1400
At the end of the day, the mound has 1,500 pounds of gravel, that is:
g - 1400 = 1500
g = 1500 + 1400
g = 2900
Therefore, the equation that best describe the given situation is:
g + 400 - 1800 = 1500
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Shelly invested $1,000 at a rate of 5% interest per year. Which equation models the value of the investment, V, after t years?
Answer:
Step-by-step explanation:
You don't say whether this is compound interest or simple interest.
I will assume it's compounding that interests you.
The appropriate formula is
A = P(1 + r)^t, where r is the interest rate as a decimal fraction, t is the time in years, and P is the original amount. Thus:
A = $1000·(1 + 0.05)^t, or A = $1000·(1.05)^t
Please note: There were apparently possible answer choices. Next time, please be sure to list such choices. Thank you.
Final answer:
The equation modeling the value of an investment, V, after t years, for an initial investment of $1,000 at a 5% annual interest rate is V = 1000(1 + 0.05)^t, incorporating the principles of compounding interest.
Explanation:
The question asks about the equation modeling the value of an investment, V, after t years, given an initial investment of $1,000 at a 5% annual interest rate. Using the formula for the future value of a single sum, V = P(1 + r)^t, where P is the principal amount ($1,000), r is the annual interest rate (5% or 0.05), and t is the number of years, we can determine that the equation modeling the value of the investment is V = 1000(1 + 0.05)^t. This formula is applied to calculate the future value of the investment, taking into account the compounding interest over a period t years.
Which choice is equivalent to the expression below? square root of negative 20
Answer:
B
Step-by-step explanation:
The expression can be written as
[tex]\sqrt{-20}[/tex]
The - can be taken out from under the radicand and a 2 can be factored out of the expression to leave you with the expression
[tex]2i\sqrt{5}[/tex]
Answer:
Correct option is:
B
Step-by-step explanation:
We have to find a expression which is similar to:
[tex]\sqrt{-20}[/tex]
Now we start solving
[tex]\sqrt{-20}[/tex] could also be written as:
[tex]\sqrt{-2\times 2\times 5}[/tex]
When we take - sign out of the square root it becomes i
i.e. [tex]\sqrt{-1}=i[/tex]
And there are two 2's inside the square root when we take square root it becomes 2
Hence, [tex]\sqrt{-20}=2i\sqrt{5}[/tex]
Hence, Correct option is:
B
What is the volume of the pyramid 7x7x8
Answer:
The volume of the pyramid is [tex]130\frac{2}{3}\ units^{3}[/tex]
Step-by-step explanation:
we know that
The volume of the pyramid is equal to
[tex]V=\frac{1}{3}BH[/tex]
where
B is the area of the base
H is the height of the pyramid
Find the area of the base B
In this problem we have a square base
[tex]B=7^{2} =49\ units^{2}[/tex]
we have
[tex]H=8\ units[/tex]
substitute
[tex]V=\frac{1}{3}(49)(8)=\frac{392}{3}\ units^{3}[/tex]
Convert to mixed number
[tex]\frac{392}{3}=\frac{390}{3}+\frac{2}{3}=130\frac{2}{3}\ units^{3}[/tex]
you do length x width x be aight divided by 3 to get 392/3
A principal of $3300 is invested at 8.5% interest, compounded anually. How much will the investment be worth after 11 years? Round your answer to the nearest dollar. Please help..
Answer:
[tex]\boxed{\$8378}[/tex]
Step-by-step explanation:
The formula for compound interest is:
A = P(1 + r)ⁿ
Data:
P = 3300
APR = 8.5 %
t = 11 yr
Calculations:
n = 11 × 12 = 132
r = 0.085/12 = 0.007 083
A = 3300(1 + 0.007 083)¹³²
= 3300 × 1.007 083¹³²
= 3300 × 2.5539
= 8378
[tex]\text{The investment will be worth }\boxed{\mathbf{\$8378}}[/tex]
A roll of fabric was 120 inches long. A customer bought 2 feet of the fabric.
How many feet of fabric were remaining?
(Hint: 1 foot = 12 inches)
OA. 12
OB. 7
OC. 118
OD.8
the correct answer is OB. 7.
need helpppppp thank you!!
Answer:
I would say 50%
Step-by-step explanation:
The answer is 50%. Hope that helps!
A dog on intravenous fluids has received 40% of the 1000 mL initially in the i.v. bag. How many mL has it received?
Answer:
The dog should receive 400 mL of the i.v. bag.
Step-by-step explanation:
40% x 1000 = 400
Answer:
The dog received 400mLStep-by-step explanation:
Givens
A dog received 40% of 100 mL of intravenous fluids.To know how many mL the dog received, we just need to find the 40% of 100 mL.
We know that 40% equals 0.40, then we multiply it
[tex]0.40(1000mL)=400mL[/tex]
Therefore, the dog received 400mL
solve for b. -1/3b = 9
Answer:
B=-27
Step-by-step explanation:
Answer:
-27
-1/3b=9
Divide both sides by -1/3 to get b by itself
-1/3b=9
/-1/3 /-1/3
b=-27
A tourist has planned a trip to cover the distance of 640 miles, driving at some constant speed. However, when he already covered a quarter of the distance, he took a rest for 1.2 hours. Then, in order to arrive at the destination on time, he increased the speed by 20 mph. How long, actually, the trip lasted?
Answer:
The trip lasted for a total of 8 hours.
Step-by-step explanation:
Distance planned = S = 640 miles
Constant speed = V
Thus the time to be taken would be = T = V/S
We have an equation 640 = VT ----- eq (a)
Time For First Quarter = T/4
speed = V
Distance = 640/4 = 160
After first quarter, there is a rest of 1.2 hours and to complete his trip on time, he increased the velocity by 20 mph.
So, the remaining distance = 640 - 160 = 480 miles.
Speed = V + 20 mph
Time remaining = [(T-T/4) - 1.2] = 3T/4 - 1.2 hours
We have an equation for remaining distance s = vt
=> 480 = (V+20)(3T/4 - 1.2) ----- eq (b)
using eq (a), we have V = 640/T. Putting it in eq (b), we have:
[tex]480 = (\frac{640}{T} + 20)(3\frac{T}{4} - 1.2)\\480 = 480 - \frac{768}{T} + 15T - 24\\=> 15T - \frac{768}{T} -24 = 0\\=> 15T^{2} - 24T - 768 = 0\\[/tex]
Solving the equation, we get T = 8 or T = -32/5(which is not possible.
So, the right answer is T = 8 hours
Quadrilateral ABCD is inscribed in a circle with m<A = (x2)°, m<B = (7x - 10)°,
and
m<C = (3x)°.
What is m<D?
Answer:
106°
Step-by-step explanation:
A quadrilateral inside a circle is a cyclic quadrilateral.
It means that the angles opposite are supplementary (add up to 180).
If we draw the quadrilateral ABCD, the angles A and C are supplementary and the angles B and D are supplementary.
Since we know A and C, we can write:
A + C = 180
x^2 + 3x = 180
x^2 +3x - 180 = 0
(x+15)(x-12) = 0
x= -15, or x = 12
Now, if we put x = -15, some angles become negative, so we disregard it and take x = 12.
Now finding B:
B = 7x - 10
B = 7(12) - 10
B = 74
We also know that B + D = 180, so:
B + D = 180
74 + D = 180
D = 180 - 74 = 106
The formula gives the height of an object in free fall at time t and acceleration g.
[tex]h = \frac{1}{2}gt^{2} [/tex]
Solve for t.
[tex]t = (2gh)^{2} [/tex]
[tex]t = 2 \sqrt{gh} [/tex]
[tex]t = \frac{ \sqrt{gh} }{2} [/tex]
[tex]t = \frac{ \sqrt{2hg} }{g} [/tex]
t must equal √2h/g but I don't see that in the choices above
Answer:
t=2hg√g
Step-by-step explanation:
took the test!
Express 0.6239 as a fraction.
The value of 0.6239 as a fraction or proportion is
A fraction is a mathematical expression that represents a part or a division of a whole. It is used to represent numbers that are not whole numbers or integers. A fraction consists of two components:
1. Numerator: The numerator is the number on the top of the fraction. It represents the quantity or part of the whole being considered.
2. Denominator: The denominator is the number at the bottom of the fraction. It represents the total number of equal parts into which the whole is divided.
Multiply and divide 0.6239 by 10000,
0.6239 = [tex]\frac{0.6239}{10000} \times[/tex] 10000
= [tex]\frac{6239}{10000}[/tex].
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what is x in -2-3x=19
Answer:
x=-7
Step-by-step explanation:
Since you are solving for x, you need to work backwards. Add 2 to both sides: -2 and 2 cancel out, and 19 plus 2 is 21. Isolate the x by dividing both sides by -3. -3 cancels out, and 21 divided by -3 is -7.
Answer:
-7
Step-by-step explanation
−2−3x=19
−2+−3x=19
−3x−2=19
Step 2: Add 2 to both sides.
−3x−2+2=19+2
−3x=21
Step 3: Divide both sides by -3.
−3x
−3
=
21
−3
x=−7
the diameter of a bicycle wheel is 0.7 meters. find the number of complete revolutions made by the wheel if the bicycle travels 440 meters. use 22/7 as an approximation for [tex]\pi[/tex]
Final answer:
To calculate the number of complete revolutions a bicycle wheel makes after traveling 440 meters, we find the wheel's circumference using its diameter and then divide the travel distance by the circumference. With a diameter of 0.7 meters and using 22/7 as an approximation for π, the wheel's circumference is 2.2 meters. The wheel makes 200 complete revolutions to cover 440 meters.
Explanation:
Finding the Number of Complete Revolutions
To find the number of complete revolutions made by a bicycle wheel when the bicycle travels a certain distance, we firstly need to calculate the circumference of the wheel. The circumference 'C' of a circle can be found using the formula C = πd, where π (Pi) is a constant (approximately 22/7 or 3.14) and 'd' is the diameter of the circle. In this case, we are given that the diameter of the bicycle wheel is 0.7 meters.
Using the approximation for π of 22/7 and the given diameter, the circumference is: C = π × d = (22/7) × 0.7 meters = 2.2 meters.
To find the number of complete revolutions 'N', we divide the total distance the bicycle travels by the circumference of the wheel: N = total distance / circumference = 440 meters / 2.2 meters. So, the number of complete revolutions the wheel makes is 200.
Find all solutions of the equation in the interval [0, 2 pi) 2 cos0-1=0
Answer:
θ = π/3, 5π/3
Step-by-step explanation:
2 cos θ - 1 = 0
2 cos θ = 1
cos θ = 1/2
θ = π/3, 5π/3
ANSWER
EXPLANATION
The given trigonometric equation is:
[tex]2 \cos( \theta) - 1 = 0[/tex]
[tex] \implies \: 2 \cos( \theta) = 1[/tex]
[tex]\implies \: \cos( \theta) = \frac{1}{2} [/tex]
The cosine ratio is positive in the first and fourth quadrants.
In the first quadrant,
[tex]\theta = \cos ^{ - 1} ( \frac{1}{2}) [/tex]
[tex]\theta = \frac{\pi}{3} [/tex]
In the fourth quadrant,
[tex]\theta =2 \pi - \cos ^{ - 1} ( \frac{1}{2}) [/tex]
[tex]\theta =2 \pi - \frac{\pi}{3} [/tex]
[tex]\theta = \frac{5\pi}{3} [/tex]
Therefore on the interval, [0,2π] the solution to the given trigonometric equation is:
[tex]\theta = \frac{\pi}{3} \: and \: \frac{5\pi}{3} [/tex]
Please help and thank you
Answer:
A
Step-by-step explanation:
Define each of the terms.
f(x) is the total level of radioactivity.
x is the total number of weeks.
[tex]\frac{1}{2}[/tex] is the weekly decay factor.
30 is the initial level of radioactivity.
What is the value of z in the equation 2(4z − 9 − 7) = 166 − 46?
Answer:
z = 19
Step-by-step explanation:
Given
2(4z - 9 - 7) = 166 - 46 ← simplify both sides
2(4z - 16) = 120 ← distribute parenthesis on left side
8z - 32 = 120 ( add 32 to both sides )
8z = 152 ( divide both sides by 8 )
z = 19
Answer:
z = 19.
Step-by-step explanation:
2(4z − 9 − 7) = 166 − 46
2(4z − 9 − 7) = 120
Divide both sides by 2:
4z − 9 − 7 = 60
4z = 76
z = 19.
Help me please will give 14 points
First, set up a proportional fraction.
[tex]\frac{5 sec}{30 gallons}[/tex] = [tex]\frac{x sec}{1gallon}[/tex]
Cross multiply
5 * 1 = 5
30 * x = 30x
So,
30x = 5
Divide 5 by 30
x = 5 / 30
x = 1 / 6 or 0.17
Do the same thing to find for 17 gallons.
30x = 85
x = 85 / 30
x = 17 / 6 or 2.8
Apply the distributive property to factor out the greatest common factor.
30+42=
Answer:
[tex]30+42=6(5+7)[/tex]
Step-by-step explanation:
Let [tex]a,b,c\in \mathbb R[/tex], according to the distributive property:
[tex]a(b+c)=ab+ac[/tex]
The prime factorization of 30 is
[tex]30=2\cdot 3\cdot 5[/tex]
The prime factorization of 42 is
[tex]42=2\cdot 3\cdot 7[/tex]
The Greatest common factor is [tex]2\times 3=6[/tex]
[tex]\implies 30+42=6\times5+6\times7[/tex]
[tex]\implies 30+42=6(5+7)[/tex]
Answer:
Step-by-step explanation:
6(5+7
Suppose you deal three cards from a regular deck of 52 cards. What is the probability that they will all be jacks?
Answer:
Probability of getting three jacks = [tex] \frac { 3 } { 5 2 } [/tex]
Step-by-step explanation:
It is given that you deal three cards from a regular deck which contains 52 cards.
We are to find the probability of getting all three Jack cards.
We know that there are a total of 4 jacks in a regular deck of 52 cards.
Therefore, the probability of getting three jacks = [tex] \frac { 3 } { 5 2 } [/tex]
3 chances of jacks out of 52 cards
Given the following diagram, find the missing measure.
Answer:
∠4 = a + b
Step-by-step explanation:
Given ∠2 = a and ∠3 = b
The sum of the 3 angles in a triangle = 180°
Subtract the sum of the 2 given angles from 180 for ∠1
∠1 = 180 - (a + b) = 180 - a - b
Now
∠1 and ∠4 form a straight angle and are supplementary, hence
∠4 = 180 - (180 - a - b) = 180 - 180 + a + b = a + b
ABC or d? I really need help and CANNOT get this wrong
Answer:
1.A. X6Y5
Step-by-step explanation:
Remove the Parenthesis calculate the product#2 I have no clue on that one.
So sorry but I simply forgot to answer your questions.
The answer to question 1 is A.
The answer to question 2 is D.
Plz help me with this
Answer: D) at least 6mm
Step-by-step explanation:
95% confidence is 2 standard deviations.
5mm + 2(0.5) = 5 + 1 = 6
The oysters must be at least 6 mm
Given right triangle XYZ, which correctly describes the locations of the sides in relation to ∠Y?
Answer:
Step-by-step explanation: a is adjacent, b is opposite, c is the hypotenuse
Answer:
D
Step-by-step explanation:
what is x in 25-3x=40
Step 1: Subtract 25 to both sides. This will cancel 25 on the left side and bring it over to the right
(25 - 25) - 3x = 40 - 25
(0) - 3x = 15
-3x = 15
Step 2: Isolate x by dividing -3 to both sides (the opposite of multiplication is division).
-3x ÷ (-3) = 15 ÷ (-3)
x = -5
Check:
25 - 3(-5) = 40
25 + 15 = 40
40 = 40 ....................................Correct!
Hope this helped!
The value of x in this equation is -5.
What is an equation?A mathematical statement consisting of an equal symbol between two algebraic expressions with the same value is known as an equation in algebra.
Equation given in the question:
25 - 3x = 40
25 - 40 = 3x
-15 = 3x
x = -5
The value of x in this equation is -5.
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