Question

I don't know how to do these: help!!

Answer 1

The number of grams of a certain radioactive substance present after t hours is given by the equation below, where Q0 represents the initial number of grams. How long will it take 4500 grams to be reduced to 2250 grams? (Express your answer to the nearest tenth.)
Q=Q_0e^(-0.36 t)

Answer 2

2250 = 4500e^(-0.36t)

Solve for t

Answer 3

what hero said. divide by 4500
take the log
divide by -0.36

Answer 4

\[2250=4500e^{-.36t}\]
\[\frac{2250}{4500}=e^{-.36t}\]
\[.5=e^{-.36t}\]
\[-.36t=\ln(.5)\]
\[t=\frac{\ln(.5)}{-.36}\] then a calculator

Answer 5

thank you! thank you!!!

Answer 6

yw