How do I solve this question?

Question

Jason had these scores on six math quizzes: 79, 80, 85, 70, 100, and 75. Sean's scores on the first five quizzes were 80, 83,75,95, and 76. What score does Sean need on his sixth quiz to give him the same average as Jason?

Answer 1

Hi Richard,

 

Let's take this methodicially. First we want to see what Jason's average is. So you add up all his math scores and divide by the number of quizzes:

 

79+80+85+70+100+75 = 489

 

489/6 = 81.5

 

Now that you know the Jason's average, you want to set up an equation using these principles. Use 'x' for the unknown sixth quiz score:

 

(80+83+75+95+76+x)/6 = 81.5

 

80+83+75+95+76+x = 489

 

409+x = 489

 

x = 80

 

So he needs an 80 on the last quiz to get the same average as Jason. Does that make sense?