Practice!

Sample Problem

Mum Mariah has 6 red eggs, 8 yellow eggs, and 3 blue eggs, all the same size. She takes some eggs out without looking, and wants to make sure she gets at least one egg of each color. At least how many eggs does she need to take out?

  eggs

Solution

The worst case scenario is that she first removes all the red and yellow eggs before she gets a single blue egg. Thus, if she removes 8 + 6 + 1 eggs, she’s guaranteed at least one of each colored egg.

In problems like this, the key is to consider the worst case scenario, where the required condition takes the longest possible amount of time to take place—this gives your answer.