Nickel-63 has half-life of about 96 years. after 336 years, about how many milligrams of an 800 mg sample will remain?
a)14 mg
b)71 mg
c)229 mg
d)656 mg

Atorch and a battery cost 2.50 altogether.the torch costs 1.50 more than the battery.what fraction of the total price is the torch? give your answer in its simplest form.