Please help! What is the base?

Suppose a ball is dropped fromca height of 6ft. it bounces back up but time it bounces, it reaches only 7/10 of its pervious height. what is the total of each height that the ball reaches after 5 bounces

Write the rational number in lowest terms 99/-15

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64