Zane, Perry and Ian had some erasers in the ratio of 2 : 3 : 5. Ian gave 40% of his erasers to Zane and Perry. As a result, Zane had the same number of erasers as Perry and Ian had 39 fewer erasers than Zane.

1. What was the percentage increase in Zane's erasers after receiving from Ian?
2. How many erasers did Perry have at first?

Zane	Perry	Ian	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 erasers that Ian gave away
= 40% x 5
= ⁴⁰₁₀₀ x 5
= 2 u

Number of erasers that Zane and Perry each had in the end
= (10 u - 3 u) ÷ 2
= 7 u ÷ 2
= 3.5 u

Increase in the number of erasers that Zane had
= 3.5 u - 2 u
= 1.5 u

Percentage increase in Zane's erasers after receiving from Ian
= ^1.5₂ x 100%
= 75%

(b)
3.5 u = 3 u + 39
3.5 u - 3 u = 39
0.5 u = 39

1 u = 39 ÷ 0.5 = 78

Number of erasers that Perry had at first
= 3 u
= 3 x 78
= 234

Answer(s): (a) 75%; (b) 234