Help brainiest to whoever right

Rewrite the following without an exponent. (5/8)-1

For one history test, keith had to answer 40 questions. of these 40 questions, keith answered 28 of them correctly. what percent did keith get on his history test? round your answer to the nearest tenth if necessary

You eat $0.85 for every cup of hot chocolate you sell. how many cups do you need to sell to earn $55.25