Question

Heidi has an average score of 78 for her first six chemistry tests. If Heidi"s scores for the first four tests were 82,78,87, and 73 respectively, what was her average score for the last two tests?

Answer 1

Answer:

(A)74

Explanation:

Let her average score on the last two tests = x.

The six scores will now be: 82,78,87,73, x and x.

Since the average score for her first six chemistry tests = 78

$\frac{82+78+87+73+x+x}{6}=78$

We then solve for x.

$\begin{gathered} 320+2x=78\times6 \\ 320+2x=468 \\ 2x=468-320 \\ 2x=148 \\ x=\frac{148}{2} \\ x=74 \end{gathered}$

Her average score for the last two tests is 74.