Mac has taken seven maths exams this year. His average mark is 78%. What mark must he get on the eighth exam to raise his average to 80%?

Answer 1

7*78 + x = 8*80
x = 94

Or, think that he was short 2 points on each of 7 tests, so he has to make them all (14) up on the last test.

Answer 2

thank you :D

Answer 3

ty