There were 217 blue, silver and white notebooks in a box. 25 white notebooks were removed from the box and the ratio of the number of blue notebooks to the number of silver notebooks to the number of white notebooks became 5 : 4 : 3. Then some black notebooks were added and the ratio of the number of white notebooks to the number of black notebooks was 3 : 9.

1. What was the ratio of the number of blue notebooks to the number of silver notebooks to the number of white notebooks at first?
2. How many notebooks were in the box in the end?

	Blue	Silver	White	Black	Total
Before	5 u	4 u	3 u + 25	0	217
Change 1	No change	No change	- 25		- 25
After 1	5 u	4 u	3 u		192
Change 2	No change	No change	No change	+ 9 u
After 2	5 u	4 u	3 u	9 u

(a)
Total number of notebooks at first
= 5 u + 4 u + 3 u + 25
= 12 u + 25

12 u + 25 = 217
12 u = 217 - 25
12 u = 192

1 u = 192 ÷ 12 = 16

Number of blue notebooks at first
= 5 u
= 5 x 16
= 80

Number of silver notebooks at first
= 4 u
= 4 x 16
= 64

Number of white notebooks at first
= 3 u + 25
= 3 x 16 + 25
= 73 

At first
Blue notebooks : Silver notebooks : White notebooks
80 : 64 : 73

(b)
Total number of notebooks in the box in the end
= 5 u + 4 u + 3 u + 9 u
= 21 u
= 336

Answer(s): (a) 80 : 64 : 73; (b) 336