I NEED QUESTION B CALCULATOR Radium has a halflife of 1656 y

I NEED QUESTION (B)

CALCULATOR Radium has a half-life of 1656 years. Determine the decay rate for radium. What percent decrease occurs in the amount of a radium in a sample over 1 year? How much of a 3 gram sample of radium is present after 20 years?

Solution

A = A0 e^-kt

we know k=0.00031 (rounding off)

let us say A0 is the initial value

A is after 1 year

A= A0 e^-0.00031*1

A = 0.9997 A0

the amount remaining after 1 year is 0.003

the percenttage decrease = 99.97