Talking through two problems from the 2005 AMC 10

I really enjoy using old AMC problems to talk about math with the boys.

These two problems gave my older son some trouble today:

These two problems from the 2005 AMC 10a gave my son trouble this morning. pic.twitter.com/RoR55nOP40

— Mike Lawler (@mikeandallie) February 5, 2018

Tonight I had a chance to talk through these problems with them.

Here’s the probability problem:

Here’s the GCD problem: