Question

Find the missing number to make the average correct. The average of 11, 17, 18, and ? is 17.

Answer 1

The missing number is:

22

Explanation:

There are 3 numbers and one more

4 numbers and your average is 17

then:

17*4 = 68

then:

11 + 17 + 18 + a = 68

46 + a = 68

a = 68 - 46

a = 22

Check:

(22 + 11 + 17 + 18)/4 = 17

68/4 = 17