PLEASE I NEED HELP ASAP

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?

Pls , the question is in the picture!

Which is the graph of f(x) = (4)x? image for option 1 image for option 2 image for option 3 image for option 4