Question

6. Takao scores a 90, an 84, and an 89 on three out of four math tests. Whatmust Takao score on the fourth test to have an 87 average (mean)?a. 87b. 88c. 85d. 84e. 86

Answer 1

Consider x as Takao's fourth score.

Then, to achieve an 87 average, we have:

`\begin{gathered} 87=(90+84+89+x)/(4) \\ x+263=4\cdot87 \\ x=348-263 \\ x=85 \end{gathered}`

Answer:

c. 85