Jamie, Risa, Nora and Isabella share the same hobby of collecting coins. The average number of coins collected by the 4 friends is 26. Risa collected 6 more coins than Nora but 16 fewer coins than Jamie. Isabella collected 4 coins fewer than Nora. Find the average number of coins collected by Risa, Nora and Isabella. Round off your answer to the nearest whole number.
Number of coins Nora collected = 1 u
Number of coins Risa collected = 1 u + 6
Number of coins Jamie collected = 1 u + 6 + 16 = 1 u + 22
Number of coins Isabella collected = 1 u - 4

Total number of coins collected
= 4 x 26
= 104

Total number of coins collected in units
= 1 u + 1 u + 6 + 1 u + 22 + 1 u - 4
= 4 u + 24

4 u + 24 = 104
4 u = 104 - 24 = 80

1 u = 80 ÷ 4 = 20

Total number of coins collected by Risa, Nora and Isabella
= 1 u + 6 + 1 u + 1 u - 4
= 3 u + 2
= 3 x 20 + 2
= 62

Average number of coins collected by Risa, Nora and Isabella
= 62 ÷ 3
≈ 21 (Round off to the nearest whole number.)

Answer(s): 21