SOLUTION: A test had 20 questions. Each correct answer was worth five points, but one point was taken off for each incorrect answer or missing answer. The test score was 70. How many quest

Algebra ->  Average -> SOLUTION: A test had 20 questions. Each correct answer was worth five points, but one point was taken off for each incorrect answer or missing answer. The test score was 70. How many quest      Log On


   

Question 860011: A test had 20 questions. Each correct answer was worth five points, but one point was taken off for each incorrect answer or missing answer. The test score was 70. How many questions were answered correctly?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=20,
5a-b=70
b=20-a
5a-(20-a)=70
5a-20+a=70
6a=90
a=15 correct and 5 wrong
15*5-5=70