Question

question
a radioactive substance has a decay rate of 0.064 per minute. how many grams of a 150 - gram sample will remain radioactive after 45 minutes? round the answer to the nearest tenth of a gram, and do not include the unit in your answer.
note: the formula for radioactive substance is $w = me^{-kt}$
sorry, thats incorrect. try again?
8.05

Explanation:

Step1: Identify values for formula

$M = 150$, $k=0.064$, $t = 45$

Step2: Substitute values into formula

$W=150\times e^{-0.064\times45}$
First calculate the exponent: $-0.064\times45=-2.88$
Then find $e^{-2.88}$. Using a calculator, $e^{-2.88}\approx0.0569$.
Multiply by 150: $W = 150\times0.0569 = 8.535$

Step3: Round the result

Rounding $8.535$ to the nearest tenth gives $8.5$

Answer:

$8.5$