Question

If you receive an 80%, 75% , 70% and 82% in four math tests, what grade do you need to on the fifth test to average an 80% in the course.Remember to set up the linear equation and solve.

Answer 1

remember the average formula

`\bar{x}=(\sum ^(\infty)_(n\mathop=0)xi)/(n)`

in this case n= total number of data and xi is each of the data

to solve this problem you know that you did a total of 5 tests and have the average and you are missing one of them, it should look like this when replacing

`80=(80+75+70+82+x)/(5)`

clear the equation to find x, like so

`\begin{gathered} 80\cdot5=80+75+70+82+x \\ 400=80+75+70+82+x \\ x=400-80-75-70-82 \\ x=93 \end{gathered}`

You must score a 93% to obtain a 80%average on the course