Question

Mike took four tests: English, Math, Science and History. He scored a 74 in English and an 84 in History. The average of the four tests was 72. Math had a better score than Science by 6 points. What was his Science score?
Reiny
English = 74
History = 84
Science = x
Math = x+6

so
(74+84+x+x+6)/4 = 72

solve for x