Question 52972
(75+63+68+x)/4=70 or (206+x)/4=70 or 280=206+x x=280-206 or x=74 the minimum scor needed on the 4 th test to maintain a 70 average on the 4 tests. 

proof (75+63+68+74)/4=70 or 280/4=70 or 70=70