Question

Christine has scored 73, 85, 70, and 63 on her previous four tests. What score does she need on her next test so that her average (mean) is 73?

Answer 1

Answer: 74

Explanation:

The mean is the average of all the values, which we find by finding the sum of each value and dividing by the total number of data points.

With 5 data points, we can use this equation to find, x, or the data point needed to obtain a mean of 73:

`(73+85+70+63+x)/(5)=73\\ 291+x=365\\x=74`

Answer 2

74

Explanation:

(73 + 85 + 70 + 63 + x)/5 = 73.

You find the average by adding all of the test scores and dividing that number by the number of tests. We had four test, so will will take that total, plus some mystery number (let's call it x), we divide that total by 5 because now there are 5 tests and not 4. We already know what we want the average to be, we want the average to be 73. We now have:

(291 + x)/5 = 73 Multiply both sides by 5

291 + x =365 Subtract 291 from both sides to get

x = 74