Jonathan, Ava, Avery and Abigail share the same hobby of collecting marbles. The average number of marbles collected by the 4 friends is 22. Ava collected 9 more marbles than Avery but 18 fewer marbles than Jonathan. Abigail collected 4 marbles fewer than Avery. Find the average number of marbles collected by Ava, Avery and Abigail. Round off your answer to the nearest whole number.
Number of marbles Avery collected = 1 u
Number of marbles Ava collected = 1 u + 9
Number of marbles Jonathan collected = 1 u + 9 + 18 = 1 u + 27
Number of marbles Abigail collected = 1 u - 4

Total number of marbles collected
= 4 x 22
= 88

Total number of marbles collected in units
= 1 u + 1 u + 9 + 1 u + 27 + 1 u - 4
= 4 u + 32

4 u + 32 = 88
4 u = 88 - 32 = 56

1 u = 56 ÷ 4 = 14

Total number of marbles collected by Ava, Avery and Abigail
= 1 u + 9 + 1 u + 1 u - 4
= 3 u + 5
= 3 x 14 + 5
= 47

Average number of marbles collected by Ava, Avery and Abigail
= 47 ÷ 3
≈ 16 (Round off to the nearest whole number.)

Answer(s): 16