Ineed to know how to answer number 10

Write a numerical expression that satisfies all of the following conditions. 1.)the only number used in the expression is 5 2.)at least one exponent other than 1 is used 3.)when the expression is evaluated, the answer is greater than 40 and less than 50

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

Which of the following are accepted without proof in a logical system? check all that apply.