Grace, Matthew, Kaylee and Risa share the same hobby of collecting beads. The average number of beads collected by the 4 friends is 28. Matthew collected 7 more beads than Kaylee but 13 fewer beads than Grace. Risa collected 3 beads fewer than Kaylee. Find the average number of beads collected by Matthew, Kaylee and Risa. Round off your answer to the nearest whole number.
Number of beads Kaylee collected = 1 u
Number of beads Matthew collected = 1 u + 7
Number of beads Grace collected = 1 u + 7 + 13 = 1 u + 20
Number of beads Risa collected = 1 u - 3

Total number of beads collected
= 4 x 28
= 112

Total number of beads collected in units
= 1 u + 1 u + 7 + 1 u + 20 + 1 u - 3
= 4 u + 24

4 u + 24 = 112
4 u = 112 - 24 = 88

1 u = 88 ÷ 4 = 22

Total number of beads collected by Matthew, Kaylee and Risa
= 1 u + 7 + 1 u + 1 u - 3
= 3 u + 4
= 3 x 22 + 4
= 70

Average number of beads collected by Matthew, Kaylee and Risa
= 70 ÷ 3
≈ 23 (Round off to the nearest whole number.)

Answer(s): 23