A total of 30 brown files and purple files are in a container. The ratio of brown files to purple files was 1 : 4. Some white files and green files were put into the container. For every 3 purple files that were already in the container, 7 green ones were added. Then, the final number of brown files and white files was ¹₅ the final number of purple files and green files. Find the total number of white and green files.

White files	Brown files	Purple files	Green files
	1x3	4x3
		3x4	7x4
1x8		5x8
5 u	3 u	12 u	28 u

The number of purple files is repeated.  Make the number of purple files the same.  LCM of 4 and 3 is 12.

The total number of purple files and green files is repeated.  Make the total number of purple and green files the same.  LCM of 40 and 5 is 40.

Total number of brown files and purple files
= 3 u + 12 u
= 15 u

15 u = 30

1 u = 30 ÷ 15 = 2

Total number of white and green files
= 5 u + 28 u
= 33 u
= 33 x 2
= 66

Answer(s): 66