Peter saved some 20-cent coins and $5 notes in his coin box. The total value of the 20-cent coins to the total value of the $5 notes he had was in the ratio 2 : 3. After $10 worth of 20-cent coins and an equal value of $5 notes were added to the coin box, the ratio of the total value of 20-cent coins to the total value of $5 notes became 8 : 11. How many of each type did Peter have in the end?

1. 20-cent coins?
2. $5 notes?

	Value of 20-cent	Value of $5	Difference in  value
Before	2x3 = 6 u	3x3 = 9 u	1x3 = 3 u
Change	+ 10	+ 10
After	8x1 = 8 u	11x1 = 11 u	3x1 =  3 u

(a)
The difference in values between 20-cent and $5 remains unchanged. Make the difference in value the same. LCM of 1 and 3 is 3.

Increase in the value of 20-cent coins after more were added
= 8 u - 6 u
= 2 u

2 u = 10

1 u = 10 ÷ 2 = 5

Value of 20-cent coins in the end
= 8 u
= 8 x 5
= $40

100¢ = $1
20¢ = $0.20 

Number of 20-cent coins in the end
= 40 ÷ 0.20
= 200

(b)
Value of $5 notes in the end
= 11 u
= 11 x 5
= $55

Number of $5 notes in the end
= 55 ÷ 5
= 11

Answer(s): (a) 200; (b) 11