Jonathan, Lily, Mason and Victoria share the same hobby of collecting cards. The average number of cards collected by the 4 friends is 23. Lily collected 7 more cards than Mason but 16 fewer cards than Jonathan. Victoria collected 2 cards fewer than Mason. Find the average number of cards collected by Lily, Mason and Victoria. Round off your answer to the nearest whole number.
Number of cards Mason collected = 1 u
Number of cards Lily collected = 1 u + 7
Number of cards Jonathan collected = 1 u + 7 + 16 = 1 u + 23
Number of cards Victoria collected = 1 u - 2

Total number of cards collected
= 4 x 23
= 92

Total number of cards collected in units
= 1 u + 1 u + 7 + 1 u + 23 + 1 u - 2
= 4 u + 28

4 u + 28 = 92
4 u = 92 - 28 = 64

1 u = 64 ÷ 4 = 16

Total number of cards collected by Lily, Mason and Victoria
= 1 u + 7 + 1 u + 1 u - 2
= 3 u + 5
= 3 x 16 + 5
= 53

Average number of cards collected by Lily, Mason and Victoria
= 53 ÷ 3
≈ 18 (Round off to the nearest whole number.)

Answer(s): 18