Henry, Zane and Eric had some stickers in the ratio of 4 : 5 : 9. Eric gave 40% of his stickers to Henry and Zane. As a result, Henry had the same number of stickers as Zane and Eric had 36 fewer stickers than Henry.

1. What was the percentage increase in Henry's stickers after receiving from Eric?
2. How many stickers did Zane have at first?

Henry	Zane	Eric	Total
4 u	5 u	9 u	18 u
+ 3.6 u		- 3.6 u
6.3 u	6.3 u	5.4 u	18 u

(a)
Number of stickers that Eric gave away
= 40% x 9
= ⁴⁰₁₀₀ x 9
= 3.6 u

Number of stickers that Henry and Zane each had in the end
= (18 u - 5.4 u) ÷ 2
= 12.6 u ÷ 2
= 6.3 u

Increase in the number of stickers that Henry had
= 6.3 u - 4 u
= 2.3 u

Percentage increase in Henry's stickers after receiving from Eric
= ^2.3₄ x 100%
= 57.5%

(b)
6.3 u = 5.4 u + 36
6.3 u - 5.4 u = 36
0.9 u = 36

1 u = 36 ÷ 0.9 = 40

Number of stickers that Zane had at first
= 5 u
= 5 x 40
= 200

Answer(s): (a) 57.5%; (b) 200