Question

After 6 biology test her has a mean of 79. What score does Ruben need on the next test to raise his average (mean) to 81?

Answer 1

Given that the mean score after 6 biology tests is 79.,

That means the total score is 6 × 79 = 474

For Ruben to have a new average of 81, that means

`\begin{gathered} (474+x)/(6+1)=81 \\ \\ \Rightarrow(474+x)/(7)=81 \\ \\ \Rightarrow474+x=567 \\ \\ \Rightarrow x=567-474 \\ \\ \Rightarrow x=93 \end{gathered}`

Therefore, Ruben need to score 93 on the next test to raise his average (mean) to 81