A in the class test %. HELP

Question

to get an A in a course you must have an average of at least 90 on four tests of 100 points each. the scores on your first three tests were 88, 90, 85. what must you score on the fourth test to get an A for the course?

Answer 1

97

90 + (90-88) + (90-85) = 90 + 2 + 5 = 97

you need to compensate for the total 7 points that other grades were < 90

add them up, 85+88+90+97 = 360

divide by 4

360/4 = 90 for the average grade