Question

Pedro's Diner is open six days a week. His income for the first five days this week was

$120, $110, $200, $300, and $140. How much must be make on the sixth day to have a
mean(average) of $200.

Answer 1

$330

Explanation:

What is mean/average?

It is the "sum of all the numbers" divided by the "number of numbers".

An average of 200 for 6 numbers means:

`Average=(SUM)/(NumberOfNumbers)\\200=(SUM)/(6)\\SUM=200*6\\SUM=1200`

THus, if we were to add the 6 numbers, we would get "1200". Let the 6th number be x, so we can write:

120 + 110 + 200 + 300 + 140 + x = 1200

870 + x = 1200

x = 1200 - 870

x = 330

To make the average $200, Pedro needs to make $330 on 6th day.