Question

Consider the eight exam scores: 71, 72, 73, 74, 75, 76, 77, and 78. What would the ninth exam have to be if the average of all nine was 75?

Answer 1

We will have the following:

We will determine the missing values as follows:

`\begin{gathered} 75=(71+72+73+74+75+76+77+78+x)/(9)\Rightarrow75=(596+x)/(9) \\ \\ \Rightarrow675=596+x\Rightarrow x=79 \end{gathered}`

So, the missing value must be 79.