There were 125 gold, green and yellow notebooks in a box. 4 yellow notebooks were removed from the box and the ratio of the number of gold notebooks to the number of green notebooks to the number of yellow notebooks became 4 : 2 : 5. Then some grey notebooks were added and the ratio of the number of yellow notebooks to the number of grey notebooks was 5 : 2.

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

	Gold	Green	Yellow	Grey	Total
Before	4 u	2 u	5 u + 4	0	125
Change 1	No change	No change	- 4		- 4
After 1	4 u	2 u	5 u		121
Change 2	No change	No change	No change	+ 2 u
After 2	4 u	2 u	5 u	2 u

(a)
Total number of notebooks at first
= 4 u + 2 u + 5 u + 4
= 11 u + 4

11 u + 4 = 125
11 u = 125 - 4
11 u = 121

1 u = 121 ÷ 11 = 11

Number of gold notebooks at first
= 4 u
= 4 x 11
= 44

Number of green notebooks at first
= 2 u
= 2 x 11
= 22

Number of yellow notebooks at first
= 5 u + 4
= 5 x 11 + 4
= 59 

At first
Gold notebooks : Green notebooks : Yellow notebooks
44 : 22 : 59

(b)
Total number of notebooks in the box in the end
= 4 u + 2 u + 5 u + 2 u
= 13 u
= 143

Answer(s): (a) 44 : 22 : 59; (b) 143