Gabriel, Joshua, Joseph and Olivia share the same hobby of collecting beads. The average number of beads collected by the 4 friends is 25. Joshua collected 9 more beads than Joseph but 18 fewer beads than Gabriel. Olivia collected 4 beads fewer than Joseph. Find the average number of beads collected by Joshua, Joseph and Olivia. Round off your answer to the nearest whole number.
Number of beads Joseph collected = 1 u
Number of beads Joshua collected = 1 u + 9
Number of beads Gabriel collected = 1 u + 9 + 18 = 1 u + 27
Number of beads Olivia collected = 1 u - 4

Total number of beads collected
= 4 x 25
= 100

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

4 u + 32 = 100
4 u = 100 - 32 = 68

1 u = 68 ÷ 4 = 17

Total number of beads collected by Joshua, Joseph and Olivia
= 1 u + 9 + 1 u + 1 u - 4
= 3 u + 5
= 3 x 17 + 5
= 56

Average number of beads collected by Joshua, Joseph and Olivia
= 56 ÷ 3
≈ 19 (Round off to the nearest whole number.)

Answer(s): 19