Question

Strontium-90 has a half-life of about 28 years. Which equation will solve the problem of how many grams of a 40 g sample

will remain after 84 years?
Oy = }(40)
y = {(40)
Oy = 40(1)
y = 40()
84

Answer 1

40 mg

Explanation:

10 = 40 (1/2)t/28 and solve for t in years. 10/40 = (1/2)t/28 log(0.25) = (t/28) log(0.5) t = 28 log(0.25) / log(0.5) years = 56 years

Answer 2

Answer:a0 = 40 mg

a1 = 20 mg after 28 years

a2 = 10 mg after another 28 years

Step-by-step explanation:Set this up as

10 = 40 (1/2)t/28

and solve for t in years.

10/40 = (1/2)t/28

log(0.25) = (t/28) log(0.5)

t = 28 log(0.25) / log(0.5) years = 56 years