A total of 45 gold pens and brown pens are in a container. The ratio of gold pens to brown pens was 1 : 4. Some silver pens and green pens were put into the container. For every 6 brown pens that were already in the container, 12 green ones were added. Then, the final number of gold pens and silver pens was ²₃ the final number of brown pens and green pens. Find the total number of silver and green pens.

Silver pens	Gold pens	Brown pens	Green pens
	1x3	4x3
		6x2	12x2
2x12		3x12
21 u	3 u	12 u	24 u

The number of brown pens is repeated.  Make the number of brown pens the same.  LCM of 4 and 6 is 12.

The total number of brown pens and green pens is repeated.  Make the total number of brown and green pens the same.  LCM of 36 and 3 is 36.

Total number of gold pens and brown pens
= 3 u + 12 u
= 15 u

15 u = 45

1 u = 45 ÷ 15 = 3

Total number of silver and green pens
= 21 u + 24 u
= 45 u
= 45 x 3
= 135

Answer(s): 135