Flynn, Cole and Fabian had some erasers in the ratio of 4 : 5 : 9. Fabian gave 40% of his erasers to Flynn and Cole. As a result, Flynn had the same number of erasers as Cole and Fabian had 36 fewer erasers than Flynn.

1. What was the percentage increase in Flynn's erasers after receiving from Fabian?
2. How many erasers did Cole have at first?

Flynn	Cole	Fabian	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 erasers that Fabian gave away
= 40% x 9
= ⁴⁰₁₀₀ x 9
= 3.6 u

Number of erasers that Flynn and Cole each had in the end
= (18 u - 5.4 u) ÷ 2
= 12.6 u ÷ 2
= 6.3 u

Increase in the number of erasers that Flynn had
= 6.3 u - 4 u
= 2.3 u

Percentage increase in Flynn's erasers after receiving from Fabian
= ^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 erasers that Cole had at first
= 5 u
= 5 x 40
= 200

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