Rael, Josiah, Owen and Alexander share the same hobby of collecting buttons. The average number of buttons collected by the 4 friends is 24. Josiah collected 9 more buttons than Owen but 12 fewer buttons than Rael. Alexander collected 2 buttons fewer than Owen. Find the average number of buttons collected by Josiah, Owen and Alexander. Round off your answer to the nearest whole number.
Number of buttons Owen collected = 1 u
Number of buttons Josiah collected = 1 u + 9
Number of buttons Rael collected = 1 u + 9 + 12 = 1 u + 21
Number of buttons Alexander collected = 1 u - 2

Total number of buttons collected
= 4 x 24
= 96

Total number of buttons collected in units
= 1 u + 1 u + 9 + 1 u + 21 + 1 u - 2
= 4 u + 28

4 u + 28 = 96
4 u = 96 - 28 = 68

1 u = 68 ÷ 4 = 17

Total number of buttons collected by Josiah, Owen and Alexander
= 1 u + 9 + 1 u + 1 u - 2
= 3 u + 7
= 3 x 17 + 7
= 58

Average number of buttons collected by Josiah, Owen and Alexander
= 58 ÷ 3
≈ 19 (Round off to the nearest whole number.)

Answer(s): 19