There were 253 white, blue and black staplers in a box. 25 black staplers were removed from the box and the ratio of the number of white staplers to the number of blue staplers to the number of black staplers became 5 : 4 : 3. Then some grey staplers were added and the ratio of the number of black staplers to the number of grey staplers was 3 : 5.

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

	White	Blue	Black	Grey	Total
Before	5 u	4 u	3 u + 25	0	253
Change 1	No change	No change	- 25		- 25
After 1	5 u	4 u	3 u		228
Change 2	No change	No change	No change	+ 5 u
After 2	5 u	4 u	3 u	5 u

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

12 u + 25 = 253
12 u = 253 - 25
12 u = 228

1 u = 228 ÷ 12 = 19

Number of white staplers at first
= 5 u
= 5 x 19
= 95

Number of blue staplers at first
= 4 u
= 4 x 19
= 76

Number of black staplers at first
= 3 u + 25
= 3 x 19 + 25
= 82 

At first
White staplers : Blue staplers : Black staplers
95 : 76 : 82

(b)
Total number of staplers in the box in the end
= 5 u + 4 u + 3 u + 5 u
= 17 u
= 323

Answer(s): (a) 95 : 76 : 82; (b) 323