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

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

i believe the correct answer is option 4.principalities were small territories that were run by russian rulers.

which statement correctly defines principalities in northern asia in the 1200s? principalities were small territories that were run by russian rulers.

hope i could ! : )

you already gave the answer

step-by-step explanation: