1. When there are two events that need to happen, we must multiply the probability of each event happening.
Shawn losing to Mike: 5/8 chance
Shawn losing to Tim: 2/7 chance
5/8 × 2/7 = 10/56 = 5/28
There's a 5/28 chance of Shawn losing to Mike and Tim.
I don't know #2, sorry :/
Hope this helps!
