Jean had some silver stamps and gold stamps in 2 boxes. In Box G, the ratio of the number of silver stamps to gold stamps was 7 : 3. In Box H, the number of silver stamps was 2 times the number of gold stamps. Jean transferred ²₃ of the gold stamps from Box G to Box H. The number of stamps in Box G became 80 and the ratio of the number of silver stamps to gold stamps in Box H became 6 : 7.

1. How many gold stamps were transferred from Box G to Box H?
2. What was the number of stamps in Box H after the transfer?

	Box G		Box H
	Silver	Gold	Silver	Gold
Comparing silver stamps and gold stamps at first	7 u	3 u	2x3 = 6 p	1x3 = 3 p
Before		3 u
Change		- 2 u		+ 2 u
After		1 u
Comparing silver stamps and gold stamps in the end	7 u	1 u	6 p	7 p

(a)
Total number of stamps in the end for Box G
= 7 u + 1 u
= 8 u

8 u = 80

1 u = 80 ÷ 8 = 10

Number of gold stamps that were transferred from Box G to Box H
= 2 u
= 2 x 10
= 20

(b)
The number of silver stamps in Box H remains unchanged.  Make the number of silver stamps in Box H the same.  LCM of 2 and 6 is 6. 

Increase in the number of gold stamps in Box H
= 7 p - 3 p
= 4 p

4 p = 2 u
4 p = 20

1 p = 20 ÷ 4 = 5

Number of stamps in Box H in the end
= 6 p + 7 p
= 13 p
= 13 x 5
= 65

Answer(s): (a) 20; (b) 65