Please need help thank you

Students are given 3 minutes for each multiple-choice question and 5 minutes for each free-response question on a test. there are 15 questions on the test, and students are given 51 minutes to take it.how many multiple-choice questions are on the test?

Wich statement could be used to explain why the function h(x)= x^3 has an inverse relation that is also a function

52 cm radius = diameter = area = circumference = circumfer