There were 143 blue, green and white staplers in a box. 23 white staplers were removed from the box and the ratio of the number of blue staplers to the number of green staplers to the number of white staplers became 2 : 4 : 9. Then some purple staplers were added and the ratio of the number of white staplers to the number of purple staplers was 9 : 2.

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

	Blue	Green	White	Purple	Total
Before	2 u	4 u	9 u + 23	0	143
Change 1	No change	No change	- 23		- 23
After 1	2 u	4 u	9 u		120
Change 2	No change	No change	No change	+ 2 u
After 2	2 u	4 u	9 u	2 u

(a)
Total number of staplers at first
= 2 u + 4 u + 9 u + 23
= 15 u + 23

15 u + 23 = 143
15 u = 143 - 23
15 u = 120

1 u = 120 ÷ 15 = 8

Number of blue staplers at first
= 2 u
= 2 x 8
= 16

Number of green staplers at first
= 4 u
= 4 x 8
= 32

Number of white staplers at first
= 9 u + 23
= 9 x 8 + 23
= 95 

At first
Blue staplers : Green staplers : White staplers
16 : 32 : 95

(b)
Total number of staplers in the box in the end
= 2 u + 4 u + 9 u + 2 u
= 17 u
= 136

Answer(s): (a) 16 : 32 : 95; (b) 136