Jayden, Gabriel, Grace and Elizabeth share the same hobby of collecting marbles. The average number of marbles collected by the 4 friends is 27. Gabriel collected 6 more marbles than Grace but 14 fewer marbles than Jayden. Elizabeth collected 2 marbles fewer than Grace. Find the average number of marbles collected by Gabriel, Grace and Elizabeth. Round off your answer to the nearest whole number.
Number of marbles Grace collected = 1 u
Number of marbles Gabriel collected = 1 u + 6
Number of marbles Jayden collected = 1 u + 6 + 14 = 1 u + 20
Number of marbles Elizabeth collected = 1 u - 2

Total number of marbles collected
= 4 x 27
= 108

Total number of marbles collected in units
= 1 u + 1 u + 6 + 1 u + 20 + 1 u - 2
= 4 u + 24

4 u + 24 = 108
4 u = 108 - 24 = 84

1 u = 84 ÷ 4 = 21

Total number of marbles collected by Gabriel, Grace and Elizabeth
= 1 u + 6 + 1 u + 1 u - 2
= 3 u + 4
= 3 x 21 + 4
= 67

Average number of marbles collected by Gabriel, Grace and Elizabeth
= 67 ÷ 3
≈ 22 (Round off to the nearest whole number.)

Answer(s): 22