Ben, Howard and Glen had some erasers in the ratio of 2 : 3 : 5. Glen gave 40% of his erasers to Ben and Howard. As a result, Ben had the same number of erasers as Howard and Glen had 22 fewer erasers than Ben.

1. What was the percentage increase in Ben's erasers after receiving from Glen?
2. How many erasers did Howard have at first?

Ben	Howard	Glen	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 Glen gave away
= 40% x 5
= ⁴⁰₁₀₀ x 5
= 2 u

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

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

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

(b)
3.5 u = 3 u + 22
3.5 u - 3 u = 22
0.5 u = 22

1 u = 22 ÷ 0.5 = 44

Number of erasers that Howard had at first
= 3 u
= 3 x 44
= 132

Answer(s): (a) 75%; (b) 132