Zeph saved some 50-cent coins and $5 notes in his coin box. The total value of the 50-cent coins to the total value of the $5 notes he had was in the ratio 1 : 3. After $132 worth of 50-cent coins and an equal value of $5 notes were added to the coin box, the ratio of the total value of 50-cent coins to the total value of $5 notes became 7 : 10. How many of each type did Zeph have in the end?

1. 50-cent coins?
2. $5 notes?

	Value of 50-cent	Value of $5	Difference in  value
Before	1x3 = 3 u	3x3 = 9 u	2x3 = 6 u
Change	+ 132	+ 132
After	7x2 = 14 u	10x2 = 20 u	3x2 =  6 u

(a)
The difference in values between 50-cent and $5 remains unchanged. Make the difference in value the same. LCM of 2 and 3 is 6.

Increase in the value of 50-cent coins after more were added
= 14 u - 3 u
= 11 u

11 u = 132

1 u = 132 ÷ 11 = 12

Value of 50-cent coins in the end
= 14 u
= 14 x 12
= $168

100¢ = $1
50¢ = $0.50 

Number of 50-cent coins in the end
= 168 ÷ 0.50
= 336

(b)
Value of $5 notes in the end
= 20 u
= 20 x 12
= $240

Number of $5 notes in the end
= 240 ÷ 5
= 48

Answer(s): (a) 336; (b) 48