Guys help me, please it's due very soon

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?

An elevator travels 310 feet in 10 seconds. at that speed, how far can't his elevator travel in 12 seconds?

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)