Help! Will mark brainliest if correct!

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?

Solve the system of equations. y= 2x y= x^2 - 15

Find the pattern and use it to list the nth term in the sequence. 6, 12, 20, 30, 42, 56, the nth term of the sequence is