Jenson saved some 10-cent coins and $1 notes in his coin box. The total value of the 10-cent coins to the total value of the $1 notes he had was in the ratio 1 : 3. After $25 worth of 10-cent coins and an equal value of $1 notes were added to the coin box, the ratio of the total value of 10-cent coins to the total value of $1 notes became 3 : 4. How many of each type did Jenson have in the end?

1. 10-cent coins?
2. $1 notes?

	Value of 10-cent	Value of $1	Difference in  value
Before	1x1 = 1 u	3x1 = 3 u	2x1 = 2 u
Change	+ 25	+ 25
After	3x2 = 6 u	4x2 = 8 u	1x2 =  2 u

(a)
The difference in values between 10-cent and $1 remains unchanged. Make the difference in value the same. LCM of 2 and 1 is 2.

Increase in the value of 10-cent coins after more were added
= 6 u - 1 u
= 5 u

5 u = 25

1 u = 25 ÷ 5 = 5

Value of 10-cent coins in the end
= 6 u
= 6 x 5
= $30

100¢ = $1
10¢ = $0.10 

Number of 10-cent coins in the end
= 30 ÷ 0.10
= 300

(b)
Value of $1 notes in the end
= 8 u
= 8 x 5
= $40

Number of $1 notes in the end
= 40 ÷ 1
= 40

Answer(s): (a) 300; (b) 40