What is (9/8) x (9/8) or (9/8) to the second power

Which expressions are equivalent to k/2 choose 2 answers: a k-2 b 2/k c 1/2k d k/2 e k+k

On saturday a souvenir shop had 125 customers.sixty four percent of the costumers paid with a credit card. how many costumers paid with cash?

I’m on question 7 it says a covered water tank is in the shape of a cylinder the tank has a 28 inch diameter and a height of 66 inches to the nearest square inch what is the surface area of the water tank