On a 20 question math test, your teacher gives you five points for every correct answer and takes away one point for each incorrect answer. If you score 70 on the test, how many did you get correct?
2 answers
the answer is 15 because 15*5=75 75-5 ( the 5 you got wrong) = 70
number correct --- x
number incorrect --- 20-x
5x -1(20-x) = 70
5x - 20 + x = 70
6x = 90
x = 90/6 = 15 , as Bob stated
number incorrect --- 20-x
5x -1(20-x) = 70
5x - 20 + x = 70
6x = 90
x = 90/6 = 15 , as Bob stated