Justin, Japheth and Tim had some stamps in the ratio of 2 : 3 : 5. Tim gave 40% of his stamps to Justin and Japheth. As a result, Justin had the same number of stamps as Japheth and Tim had 46 fewer stamps than Justin.

1. What was the percentage increase in Justin's stamps after receiving from Tim?
2. How many stamps did Japheth have at first?

Justin	Japheth	Tim	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 stamps that Tim gave away
= 40% x 5
= ⁴⁰₁₀₀ x 5
= 2 u

Number of stamps that Justin and Japheth each had in the end
= (10 u - 3 u) ÷ 2
= 7 u ÷ 2
= 3.5 u

Increase in the number of stamps that Justin had
= 3.5 u - 2 u
= 1.5 u

Percentage increase in Justin's stamps after receiving from Tim
= ^1.5₂ x 100%
= 75%

(b)
3.5 u = 3 u + 46
3.5 u - 3 u = 46
0.5 u = 46

1 u = 46 ÷ 0.5 = 92

Number of stamps that Japheth had at first
= 3 u
= 3 x 92
= 276

Answer(s): (a) 75%; (b) 276