Question

An unknown substance weighs 26.28kg when it is first brought to the lab. After a week in the lab, a technician weighs it again and finds it weighs 9.47kg. Assuming the substance is decaying exponentially, calculate the decay factor from week to week.

Answer 1

Answer:

Decaying rate is 6.3965% per week.

Step-by-step explanation:

Given that an unknown substance weighs 26.28kg when it is first brought to the lab. After a week in the lab, a technician weighs it again and finds it weighs 9.47kg.

Since we assume the substance is decalying exponentially let us assume decay rate is r%

$P(t) = 26.28(1-r/100)^t$, where t represents the number of weeks form the beginning.

When t=1, P = 9.47

Substitute to get

$P(1) = 9.47 = 26.28(1-r/100)\\\\r =6.3965$

Decaying rate is 6.3965% per week.