SOLUTION: Any help with this homework question? Not sure of the formula. Thank you! "The amount of a sample of a radioactive substance remaining after t years is given by a function of th

Question 916506: Any help with this homework question? Not sure of the formula. Thank you!
"The amount of a sample of a radioactive substance remaining after t years is given by a function of the form Q(t) = Q0e^-0.0001t. At the end of 5,000 years, 50 grams of the substance remain. How many grams were present initially? Round your answer to the nearest hundredth gram."
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
let f = q(t)
let p = q(0)

your equation becomes:
f=p*e^(-.0001*t)

replace f with 50 and t with 5000 to get:
50 = p*e^(-.0001*5000)

divide both sides of this equation by e^(-.0001*5000) to get:
50/e^(-.0001*5000) = p
use your calculator to solve for p to get:
p = 82.43606354 which you can round as desired.

confirm by replacing p with 82.43606354 in the original equation to get:
f = p*e^(-.0001*5000) becomes:
50 = 82.43606354*e^(-.0001*5000) which becomes:
50 = 50

this confirms the solution is good.

RELATED QUESTIONS
The amount of grams "A" of a certain radioactive substance dumped in the Craney Island... (answered by stanbon)

a radioactive substance has a half life of 120 days.if an original sample of the... (answered by ankor@dixie-net.com)

The mass of a radioactive substance follows a continuous exponential decay model, with a... (answered by ankor@dixie-net.com)

Please help me with this question. 2. The rate of decay of a radioactive substance is... (answered by stanbon)

Please help me solve this question 4. An initial 65 mg sample of a radioactive... (answered by josgarithmetic)

Please help me solve this question. An initial 65 mg sample of a radioactive substance (answered by Theo)

A sample of a radioactive substance has an initial mass of 31.9 mg. This substance... (answered by ikleyn)

A scientist begins with 250 grams of a radioactive substance. After 250 minutes, the... (answered by Boreal)

A scientist begins with 250 grams of a radioactive substance. After 250 minutes, the... (answered by ankor@dixie-net.com,greenestamps)