There were 183 green, black and brown notebooks in a box. 12 brown notebooks were removed from the box and the ratio of the number of green notebooks to the number of black notebooks to the number of brown notebooks became 4 : 2 : 3. Then some white notebooks were added and the ratio of the number of brown notebooks to the number of white notebooks was 3 : 2.

1. What was the ratio of the number of green notebooks to the number of black notebooks to the number of brown notebooks at first?
2. How many notebooks were in the box in the end?

	Green	Black	Brown	White	Total
Before	4 u	2 u	3 u + 12	0	183
Change 1	No change	No change	- 12		- 12
After 1	4 u	2 u	3 u		171
Change 2	No change	No change	No change	+ 2 u
After 2	4 u	2 u	3 u	2 u

(a)
Total number of notebooks at first
= 4 u + 2 u + 3 u + 12
= 9 u + 12

9 u + 12 = 183
9 u = 183 - 12
9 u = 171

1 u = 171 ÷ 9 = 19

Number of green notebooks at first
= 4 u
= 4 x 19
= 76

Number of black notebooks at first
= 2 u
= 2 x 19
= 38

Number of brown notebooks at first
= 3 u + 12
= 3 x 19 + 12
= 69 

At first
Green notebooks : Black notebooks : Brown notebooks
76 : 38 : 69

(b)
Total number of notebooks in the box in the end
= 4 u + 2 u + 3 u + 2 u
= 11 u
= 209

Answer(s): (a) 76 : 38 : 69; (b) 209