1998 CEMC Gauss (Grade 7) Problems/Problem 4

Problem 4

Jean writes five tests and achieves the marks shown on the graph. What is her average mark on these five tests?

[insert bar graph with 5 bars: 80, 70, 60, 90, 80]

$\text{(A)}\ 74 \qquad \text{(B)}\ 76 \qquad \text{(C)}\ 70 \qquad \text{(D)}\ 64 \qquad \text{(E)}\ 79$

Solution

The average of the $5$ tests is $\frac{80+70+60+90+70}{5} = \boxed{74}.$

The answer is $\text{(A)}$.

-edited by coolmath34


Solution

When 80 + 70 + 60 + 90 + 80 added together the total is 380. Next 380 ÷ 5 = 76

 80
 70
 60
 90
 80

+___

380 ÷ 5 = 76

Therefore when 80+70+60+90+80 are added together the total is 380 ÷ 5 = 76 so (B) 76 is correct answer.

-edited by De-math-wiz