Question

The half-life of strontium -90 is approximately 29 Year’s . How much of a 150 g sample of strontium-90 will remain after 116 years

Answer 1

The half-life is 29 years.
116 : 29 = 4
So we will have 4 periods of half-life:
( 1/2 )^4 = 1/16
150 g * 1/16 = 9.375 g
Answer:
9.375 g of strontium -90 will remain after 116 years.