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fgiga [73]
3 years ago
5

A radioactive substance has a continuous decay rate of 0.056 per minute. How many grams of a 120 gram sample will remain radioac

tive after 40 minutes? Round the answer to the nearest tenth of a gram, and do not include the unit in your answer.
Mathematics
1 answer:
sammy [17]3 years ago
5 0

Answer:

The mass of the radioactive sample after 40 minutes is 12.8 g.

Step-by-step explanation:

The mass of the sample can be found by using the exponential decay equation:

N_{t} = N_{0}e^{-\lambda t}

Where:

N(t): is the amount of the sample at time t =?

N₀: is the initial quantity of the sample = 120 g

t = 40 min

λ: is the decay constant =  0.056 min⁻¹

Hence, the mass of the sample after 40 min is:

N_{t} = N_{0}e^{-\lambda t} = 120g*e^{-0.056min^{-1}*40 min} = 12.8 g

     

Therefore, the mass of the radioactive sample after 40 minutes is 12.8 g.

I hope it helps you!

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3 years ago
Find the inverse of function f. f(x)=9x+7 A. B. C. D.
9966 [12]

Answer:

y = (x-7)/9

Step-by-step explanation:

y = 9x + 7

x = 9y + 7

x - 7 = 9y

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8 0
3 years ago
THEIR AGES
snow_tiger [21]

Answer:

Tom’s age is 7 years

Mary’s age is 13 years

Step-by-step explanation:

Since we do not know the ages, let’s represent the ages by variables at first.

Let m represent mary’s age will t represent Tom’s age.

Now, let’s proceed to have equations.

Adding square of Tom’s age (t^2) to mary’s age give 62

t^2 + m = 62 •••••••(i)

Adding square of mary’s age (m^2) to Tom’s age give 176

m^2 + t = 176 •••••••(ii)

Now, to get the individual ages, we will need to solve both equations simultaneously.

Solving both equations simultaneously without mathematical softwares can be a little hard.

By the use of mathematical software ( wolfram alpha to be specific), we can input both equations and allow the software to solve.

By inputing these equations, we have the values of t to be 7 and m to be 13

And if we try to check by inspection, we can see that these values are actually correct.

7^2 + 13 = 62

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6 0
3 years ago
One smartphone plan costs $52 per month for talk and messaging and $8 per gigabyte of data used each month. A second smartphone
valina [46]

Answer:

Both plans would cost $100 if 6 gigabytes of data are used.

Explanation:

From the question, the system of equation are correctly represented by using small letter c to represent the total cost in dollars for both equations as already assumed in the question as follows:

c = 52 + 8d ........................... (1)

c = 82 + 3d ........................... (2)

Since c is common to both, equations (1) and (2) can therefore be equated and d solved for as follows:

52 + 8d = 82 + 3d

8d - 3d = 82 - 52

5d = 30

d = 30 / 5

d = 6

Substituting d = 6 into equation (1), we have:

c = 52 + (8 * 6)

c = 52 + 48

c = 100

Since d = 6 and c = 100, it therefore implies that both plans would cost $100 if 6 gigabytes of data are used.

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2 years ago
Which rational number represents a decrease in water level from 8 feet to 6 feet?
Serggg [28]

Answer:

C

Step-by-step explanation:

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