Question

Massachusetts has a population of over 6,550,000 people. The maximum number of hairs that can grow on a human head is 500,000. Prove that there are at least 14 residents of Massachusetts who have the same number of hairs on their heads.

Answer 1

So, basically, you can do this:

500,001*14<6,550,000.

This works because there is one person that can have 0 hairs, 1 hair, 2 hair and so on until we reach 500,000 hairs. Then, there has to be a repeat. So, we can do this fourteen times. Then, we can see that there are at least 14 people with a certain amount of hairs.