What is the answer to this i don't know it and i am lost and confused can u me

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?

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

How does reflecting or rotating a figure change the interior angles of the figure?