There were 257 grey, gold and green notebooks in a box. 5 green notebooks were removed from the box and the ratio of the number of grey notebooks to the number of gold notebooks to the number of green notebooks became 5 : 4 : 9. Then some white notebooks were added and the ratio of the number of green notebooks to the number of white notebooks was 9 : 5.

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

	Grey	Gold	Green	White	Total
Before	5 u	4 u	9 u + 5	0	257
Change 1	No change	No change	- 5		- 5
After 1	5 u	4 u	9 u		252
Change 2	No change	No change	No change	+ 5 u
After 2	5 u	4 u	9 u	5 u

(a)
Total number of notebooks at first
= 5 u + 4 u + 9 u + 5
= 18 u + 5

18 u + 5 = 257
18 u = 257 - 5
18 u = 252

1 u = 252 ÷ 18 = 14

Number of grey notebooks at first
= 5 u
= 5 x 14
= 70

Number of gold notebooks at first
= 4 u
= 4 x 14
= 56

Number of green notebooks at first
= 9 u + 5
= 9 x 14 + 5
= 131 

At first
Grey notebooks : Gold notebooks : Green notebooks
70 : 56 : 131

(b)
Total number of notebooks in the box in the end
= 5 u + 4 u + 9 u + 5 u
= 23 u
= 322

Answer(s): (a) 70 : 56 : 131; (b) 322