Neave, Ken and Jeremy had some marbles in the ratio of 2 : 3 : 5. Jeremy gave 40% of his marbles to Neave and Ken. As a result, Neave had the same number of marbles as Ken and Jeremy had 40 fewer marbles than Neave.

1. What was the percentage increase in Neave's marbles after receiving from Jeremy?
2. How many marbles did Ken have at first?

Neave	Ken	Jeremy	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 marbles that Jeremy gave away
= 40% x 5
= ⁴⁰₁₀₀ x 5
= 2 u

Number of marbles that Neave and Ken each had in the end
= (10 u - 3 u) ÷ 2
= 7 u ÷ 2
= 3.5 u

Increase in the number of marbles that Neave had
= 3.5 u - 2 u
= 1.5 u

Percentage increase in Neave's marbles after receiving from Jeremy
= ^1.5₂ x 100%
= 75%

(b)
3.5 u = 3 u + 40
3.5 u - 3 u = 40
0.5 u = 40

1 u = 40 ÷ 0.5 = 80

Number of marbles that Ken had at first
= 3 u
= 3 x 80
= 240

Answer(s): (a) 75%; (b) 240