Leah, Joseph, Michael and Scarlett share the same hobby of collecting buttons. The average number of buttons collected by the 4 friends is 22. Joseph collected 7 more buttons than Michael but 12 fewer buttons than Leah. Scarlett collected 2 buttons fewer than Michael. Find the average number of buttons collected by Joseph, Michael and Scarlett. Round off your answer to the nearest whole number.
Number of buttons Michael collected = 1 u
Number of buttons Joseph collected = 1 u + 7
Number of buttons Leah collected = 1 u + 7 + 12 = 1 u + 19
Number of buttons Scarlett collected = 1 u - 2

Total number of buttons collected
= 4 x 22
= 88

Total number of buttons collected in units
= 1 u + 1 u + 7 + 1 u + 19 + 1 u - 2
= 4 u + 24

4 u + 24 = 88
4 u = 88 - 24 = 64

1 u = 64 ÷ 4 = 16

Total number of buttons collected by Joseph, Michael and Scarlett
= 1 u + 7 + 1 u + 1 u - 2
= 3 u + 5
= 3 x 16 + 5
= 53

Average number of buttons collected by Joseph, Michael and Scarlett
= 53 ÷ 3
≈ 18 (Round off to the nearest whole number.)

Answer(s): 18