Find the product of 3 1/8 and 12/7. express your answer in simplest form

What is the value of the expression below? (81^2)^1/8

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?