Billy, Sam and Oscar had some stickers in the ratio of 2 : 3 : 5. Oscar gave 40% of his stickers to Billy and Sam. As a result, Billy had the same number of stickers as Sam and Oscar had 32 fewer stickers than Billy.

1. What was the percentage increase in Billy's stickers after receiving from Oscar?
2. How many stickers did Sam have at first?

Billy	Sam	Oscar	Total
2 u	3 u	5 u	10 u
+ 2 u		- 2 u
3.5 u	3.5 u	3 u	10 u

(a)
Number of stickers that Oscar gave away
= 40% x 5
= ⁴⁰₁₀₀ x 5
= 2 u

Number of stickers that Billy and Sam each had in the end
= (10 u - 3 u) ÷ 2
= 7 u ÷ 2
= 3.5 u

Increase in the number of stickers that Billy had
= 3.5 u - 2 u
= 1.5 u

Percentage increase in Billy's stickers after receiving from Oscar
= ^1.5₂ x 100%
= 75%

(b)
3.5 u = 3 u + 32
3.5 u - 3 u = 32
0.5 u = 32

1 u = 32 ÷ 0.5 = 64

Number of stickers that Sam had at first
= 3 u
= 3 x 64
= 192

Answer(s): (a) 75%; (b) 192