What is the distance, Will mark brainlist first 1

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?

Based on the figures as marked, /\rqs = —

Sole the equation 6n + 9 = -3n - 21 - 6 for n