A total of 35 brown pencils and gold pencils are in a container. The ratio of brown pencils to gold pencils was 2 : 5. Some black pencils and silver pencils were put into the container. For every 1 gold pencils that were already in the container, 6 silver ones were added. Then, the final number of brown pencils and black pencils was ²₇ the final number of gold pencils and silver pencils. Find the total number of black and silver pencils.

Black pencils	Brown pencils	Gold pencils	Silver pencils
	2x1	5x1
		1x5	6x5
2x5		7x5
8 u	2 u	5 u	30 u

The number of gold pencils is repeated.  Make the number of gold pencils the same.  LCM of 5 and 1 is 5.

The total number of gold pencils and silver pencils is repeated.  Make the total number of gold and silver pencils the same.  LCM of 35 and 7 is 35.

Total number of brown pencils and gold pencils
= 2 u + 5 u
= 7 u

7 u = 35

1 u = 35 ÷ 7 = 5

Total number of black and silver pencils
= 8 u + 30 u
= 38 u
= 38 x 5
= 190

Answer(s): 190