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3 years ago

The half-life of plutonium-241 is 14.4 years. How much of the original 3.6 grams of this

1 answer:

5 0

$\textit{Amount for Exponential Decay using Half-Life} \\\\ A=P\left( \frac{1}{2} \right)^{\frac{t}{h}}\qquad \begin{cases} A=\textit{current amount}\\ P=\textit{initial amount}\dotfill &3.6\\ t=\textit{elapsed time}\dotfill &45\\ h=\textit{half-life}\dotfill &14.4 \end{cases} \\\\\\ A=3.6\left( \frac{1}{2} \right)^{\frac{45}{14.4}}\implies A=3.6\left( \frac{1}{2} \right)^{3.125}\implies A\approx 0.41265$

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ICE Princess25 [194]

Answer:

7 years older than jason

Step-by-step explanation:

-10 + 3 = -7 is an equation

7 years older than jason cannot be converted into an equation bc there's not enough info, so it is not.

x + 7 = 20 is an equation

three times a number is twelve, so 3x = 12, which is an equation

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3 years ago

Rochelle and her father watched a football game on monday night the quarterback threw the all a total of 318 yards how many feet

prohojiy [21]

Answer:

954 feet.

Step-by-step explanation:

We have been given that the quarterback threw the ball a total of 318 yards. We are asked to find the number of feet the quarter back throw the ball.

We know that 1 yard equals to 3 feet.

To convert 318 yards in feet, we will multiply 318 by 3 as:

$318\text{ yards}\times \frac{\text{3 feet}}{\text{Yard}}=318\times\text{3 feet}=954\text{ feet}$

Therefore, the quarter back threw the ball a total of 954 feet.

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3 years ago

Conan installs windows for a living and has propped his ladder against a customer's

Luden [163]

Answer:

Step-by-step explanation:

By the Pythagorean Theorem

h^2=x^2+y^2

Which means that the hypotenuse (longest side of a right triangle) squared is equal to the sum of its squared sides. In this case we are given the side lengths of 8 and 15 feet.

h^2=8^2+15^2

h^2=64+225

h^2=289

h=17 ft

The ladder is 17 feet long.

3 0

3 years ago

Sam invested $5000 in a GIC earning 8% compound interest per year. 1he interest gets added to the amount invested, so the next y

kkurt [141]

Answer:

Sams Investment will be $9995.62

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Suppose that scores on a knowledge test are normally distributed with a mean of 60 and a standard deviation of 4.3. Scores on an

Sphinxa [80]

Question:

(c) Boris also took a logic test. His z-score on that test was +0.93 . Does this change the answer to which test Boris performed better on? Explain your answer using z-scores.

Answer:

The answers to the questions are;

(a) Based on the z score, Boris perform better on his aptitude test.

(b) Based on the z score, Callie perform better on his knowledge test .

Yes as Boris now performed best on the logic test.

Step-by-step explanation:

The z-score of a score is a measurement of the score withe respect to its distance from the mean as a factor of the standard deviation.

To solve the question, we note that we are required to find the z score as follows.

z score is given by $z = \frac{x -\mu}{\sigma}$

Where:

z = Standard score

x = Score

σ = Standard deviation

μ = Mean

(a) To find out which test did Boris performed better usin z score, we have

Boris scored a

57 on the knowledge test and

106 on the aptitude test

Therefore the z sore for the knowledge test is

$z = \frac{x -\mu}{\sigma}$

Here

x = 57

μ = 60

σ = 4.3

Therefore

$z_{knowledge} = \frac{57 -60}{4.3}$ = -3/4.3 = -30/43 = -0.6977

The z sore for Boris on the aptitude test is

Here

x = 106

μ = 110

σ = 7.1

$z_{aptitude} = \frac{106 -110}{7.1}$ = -40/17 = -0.5634

Based on the z score, Boris perform better on the aptitude test as his z score is higher (on the number line), --0.5634, compared to the z score on the knowledge test , -0.6977

(b) For Callie we have

Callie scored a

63 on the knowledge test and

114 on the aptitude test

Therefore the z sore for the knowledge test is

$z = \frac{x -\mu}{\sigma}$

Here

x = 63

μ = 60

σ = 4.3

Therefore

$z_{knowledge} = \frac{63 -60}{4.3}$ = 3/4.3 = 30/43 = 0.6977

The z sore for Callie on the aptitude test is

Here

x = 114

μ = 110

σ = 7.1

$z_{aptitude} = \frac{114 -110}{7.1}$ = 40/17 = 0.5634

Based on the z score, Callie perform better on the knowledge test as his z score is higher (on the number line), 0.6977, compared to the z score on the aptitude test , 0.5634.

$z_{aptitude}$ = - 0.5634 then

$z_{logic}$ > $z_{knowledge}$ > $z_{aptitude}$

Therefore Boris now performed best on the logic test.

6 0

3 years ago