The average of three numbers is 20. Two of them are 15 and 22. What is the third?
Correct answer: A. 23
The three numbers must add up to 3 × 20 = 60. The third is 60 − 15 − 22 = 23. Check: (15 + 22 + 23) ÷ 3 = 60 ÷ 3 = 20. Whenever an average is given, convert it into a total first by multiplying by the number of items.
easy