A test is worth 50 points. Multiple- choice questions are worth 1 point, and short answer questions are worth 3 points. if the test has 20 questions, how many multiple-choice questions are there?
Am + 3s =20
B.m + 3s + 20 =50
Cm + 3s = 50
Dm + s + 50
Am + 3s =20
Cm + 3s = 50
Dm + s + 50