Question

Fourteen-year-old Shirley collects one coin from every country that she visits. If she currently has collected 18 coins and wants to accumulate at least 82 coins by the time she is 30, what is the minimum number of countries she should visit on average each year until then?

Answer 1

30 years - 14 years = 16 years
82 coins  - 18 coins = 64 coins
64/16 = 4 coins per year or 4 countries per year

Shirley should visit about 4 countries per year.