Question

The average of manny's three tests is an 84. what must he get on a 4th test to raise his average to a 87

Answer 1

(X+Y+Z)/3=84  X,Y,Z IS THE THREE UNKNOWN SCORES.TO KNOW THE TOTAL , MULTIPLY THE 84 BY 3.
84*3=252
(252+H)/4=87  H IS THE FOURTH GRADE HE SHOULD HE IF HE WANTS HIS AVERAGE TO BE 87
87*4=348
252+H=348
H=348-252
H=96