Question

Kaci earned scores of 78, 88, 87, and 91 on her first four science tests. Shehas one more test to take and wants to get an average score of 80 or more on hertests.The following is the inequality that represents this situation, where I is the score ofher fifth test(78+88+87+91+x)5> 80What is the minimum score Kaci can receive on her fifth test to have an averagescore of at least 80?

Answer 1

Given:

Kaci earned scores of 78, 88, 87, and 91 on her first four science tests.

She has one more test to take and wants to get an average score of 80 or more on her tests.

Let the score of the final test = x

So, the average of the scores will be equal to or greater than 80

So, we have the following inequality

`(78+88+87+91+x)/(5)\ge80`

Solve for x:

`\begin{gathered} (78+88+87+91+x)/(5)\ge80\rightarrow*5 \\ 78+88+87+91+x\ge80*5 \\ 344+x\ge400 \\ x\ge400-344 \\ x\ge56 \end{gathered}`

So, the minimum score will be 56