Question

A penny collection contains twelve 1967 pennies, seven 1968 pennies, and eleven 1971 pennies. If you are to pick some pennies without looking at the dates, how many must you pick to be sure of getting at least four pennies from the same year?.

Answer 1

Pick at least four pennies to be sure of getting at least four pennies from the same year.

Explanation:

To be sure of getting at least four pennies from the same year, you would need to pick at least four 1967 pennies, four 1968 pennies, or four 1971 pennies. Since these are the three smallest groups of pennies, you would need to pick at least four pennies to be sure of getting at least four pennies from the same year.