A total of 63 yellow pencils and black pencils are in a container. The ratio of yellow pencils to black pencils was 1 : 2. Some green pencils and red pencils were put into the container. For every 6 black pencils that were already in the container, 4 red ones were added. Then, the final number of yellow pencils and green pencils was ⁴₅ the final number of black pencils and red pencils. Find the total number of green and red pencils.

Green pencils	Yellow pencils	Black pencils	Red pencils
	1x3	2x3
		6x1	4x1
4x2		5x2
5 u	3 u	6 u	4 u

The number of black pencils is repeated.  Make the number of black pencils the same.  LCM of 2 and 6 is 6.

The total number of black pencils and red pencils is repeated.  Make the total number of black and red pencils the same.  LCM of 10 and 5 is 10.

Total number of yellow pencils and black pencils
= 3 u + 6 u
= 9 u

9 u = 63

1 u = 63 ÷ 9 = 7

Total number of green and red pencils
= 5 u + 4 u
= 9 u
= 9 x 7
= 63

Answer(s): 63