The mean value of 8 numbers is 17. Three of these numbers (9, 11, and 20) are discarded.

What is the mean value of the 5 remaining numbers?

19.2

Step-by-step explanation:

You get the mean of a set of numbers by adding them and dividing the sum by how many numbers there are. In this case, you don't know what the individual 8 numbers are, but you can find out what they add up to.

Mean = (sum) / 8

17 = (sum) / 8

17 x 8 = sum

136 = sum

Now take out the numbers 9, 11, 20, which reduces the sum by 40. There are 5 numbers left and they add up to 136 - 40 = 96.

The new mean is 96 / 5 = 19.2