A total of 200 black folders and green folders are in a container. The ratio of black folders to green folders was 1 : 9. Some silver folders and purple folders were put into the container. For every 4 green folders that were already in the container, 3 purple ones were added. Then, the final number of black folders and silver folders was ²₇ the final number of green folders and purple folders. Find the total number of silver and purple folders.

Silver folders	Black folders	Green folders	Purple folders
	1x4	9x4
		4x9	3x9
2x9		7x9
14 u	4 u	36 u	27 u

The number of green folders is repeated.  Make the number of green folders the same.  LCM of 9 and 4 is 36.

The total number of green folders and purple folders is repeated.  Make the total number of green and purple folders the same.  LCM of 63 and 7 is 63.

Total number of black folders and green folders
= 4 u + 36 u
= 40 u

40 u = 200

1 u = 200 ÷ 40 = 5

Total number of silver and purple folders
= 14 u + 27 u
= 41 u
= 41 x 5
= 205

Answer(s): 205