The red/blue urn question in the article isn't super duper hard right? It's at a level where it's a very hard question (but still doable) for a 16 year old high

The red/blue urn question in the article isn't super duper hard right? It's at a level where it's a very hard question (but still doable) for a 16 year old high schooler I think? b = number of blue balls in second urn. P(both same color) = P(both blue) + P(both red) = P(first urn red) * P(second urn red) + P(first urn blue) * P(second urn blue) 0.44 = 4/10 * 16/(16+b) + 6/10 * b/(16+b) Multiply both sides by 10(16+b) and simplify: b = 4