Lizzy: Bryan's score on a math exam is 20. Jen scored 10 more than Bryan while Sammy scored 2 fewer than Jen. If the math exam has 35 points in all, how many mistakes did Sammy make?.
Me: Hmmm, let me think. I think this is the detailed solution:
Jen scored 20 + 10 = 30 on the exam. Sammy scored two less, so his score was30 - 2 = 28. Thus, Sammy made 35 - 28 = 7 mistakes. Final answer: 7.