Question

To pass a course with a B grade a student must have an average of 80 or greater. The students grades on three test are 80, 81 and 70. Find what score the student must get on the next test to get a B average or better.

Answer 1

Given that the student's grades on three tests are 80, 81 and 70

Let the student's grade on the fourth test be X

In order to pass the course, the student must have an average of 80 or greater.

Hence,

`\begin{gathered} (80+81+70+X)/(4)\ge80 \\ (231+X)/(4)\ge80 \\ 231+X\ge320 \\ X\ge320-231 \\ X\ge89 \end{gathered}`

The score the student must get on the next test to get a B average or better is greater than or equal to 89