There were 322 silver, purple and gold notebooks in a box. 18 gold notebooks were removed from the box and the ratio of the number of silver notebooks to the number of purple notebooks to the number of gold notebooks became 5 : 4 : 7. Then some pink notebooks were added and the ratio of the number of gold notebooks to the number of pink notebooks was 7 : 3.

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

	Silver	Purple	Gold	Pink	Total
Before	5 u	4 u	7 u + 18	0	322
Change 1	No change	No change	- 18		- 18
After 1	5 u	4 u	7 u		304
Change 2	No change	No change	No change	+ 3 u
After 2	5 u	4 u	7 u	3 u

(a)
Total number of notebooks at first
= 5 u + 4 u + 7 u + 18
= 16 u + 18

16 u + 18 = 322
16 u = 322 - 18
16 u = 304

1 u = 304 ÷ 16 = 19

Number of silver notebooks at first
= 5 u
= 5 x 19
= 95

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

Number of gold notebooks at first
= 7 u + 18
= 7 x 19 + 18
= 151 

At first
Silver notebooks : Purple notebooks : Gold notebooks
95 : 76 : 151

(b)
Total number of notebooks in the box in the end
= 5 u + 4 u + 7 u + 3 u
= 19 u
= 361

Answer(s): (a) 95 : 76 : 151; (b) 361