SAT Subject Test Mathematics Level 1

Example 7

The key to almost every SAT Subject Test averages question is to think about
the sum. Everybody knows the standard averages formula:

Perhaps less familiar, but often more useful, is this other version of the
averages formula:

Sum of  the terms   =   Average ×   Number  of  terms

George’s average after four tests is 92. To find out what effect a 77 on test
number five will have, calculate the sum of the first four scores:

Sum=Average ×   Number  =   92×4    =   368

George’s    average (arithmetic mean)   score   on  the first   four    English tests

of  the semester    is  92. If  he  earns   a   score   of  77  on  the fifth   test,   what

will    his new average be?

1.

(A) 84.5

(B) 86.0

(C) 87.5

(D) 88.0

(E) 89.0