Harry, Japheth and George had some coins in the ratio of 3 : 4 : 7. George gave 40% of his coins to Harry and Japheth. As a result, Harry had the same number of coins as Japheth and George had 21 fewer coins than Harry.

1. What was the percentage increase in Harry's coins after receiving from George?
2. How many coins did Japheth have at first?

Harry	Japheth	George	Total
3 u	4 u	7 u	14 u
+ 2.8 u		- 2.8 u
4.9 u	4.9 u	4.2 u	14 u

(a)
Number of coins that George gave away
= 40% x 7
= ⁴⁰₁₀₀ x 7
= 2.8 u

Number of coins that Harry and Japheth each had in the end
= (14 u - 4.2 u) ÷ 2
= 9.8 u ÷ 2
= 4.9 u

Increase in the number of coins that Harry had
= 4.9 u - 3 u
= 1.9 u

Percentage increase in Harry's coins after receiving from George
= ^1.9₃ x 100%
= 63.333333333333%

(b)
4.9 u = 4.2 u + 21
4.9 u - 4.2 u = 21
0.7 u = 21

1 u = 21 ÷ 0.7 = 30

Number of coins that Japheth had at first
= 4 u
= 4 x 30
= 120

Answer(s): (a) 63.333333333333%; (b) 120