Gillian, Sarah and Yoko had 1170 stamps. Sarah won some of the stamps from Gillian and as a result, Sarah's stamps increased by 20%. Yoko then won some stamps from Sarah and Yoko's stamps increased by 50%. Finally, Yoko lost some of her stamps to Gillian and Gillian's stamps increased by 25%. In the end, they realised that they each had an equal number of stamps. How many percent less did Gillian have in the end than what she had at first? Correct your answer to 1 decimal place.

Gillian	Sarah	Yoko
1170
	5 u
- 1 u	+ 1 u
	6 u
		2 p
	- 1 p	+ 1 p
		3 p
4 boxes
+ 1 box		- 1 box
5 boxes
1 group	1 group	1 group

20% = ²⁰₁₀₀ = ¹₅
50% = ⁵⁰₁₀₀ = ¹₂
25% = ²⁵₁₀₀ = ¹₄

Working backwards.

3 groups = 1170

1 group = 1170 ÷ 3 = 390

1 group = 5 boxes
5 boxes = 390

1 box = 390 ÷ 5 = 78

1 group + 1 box = 3 p
390 + 78 = 3 p
3 p = 468

1 p = 468 ÷ 3 = 156

1 p = 1 x 156 = 156

1 group + 1 p = 6 u
390 + 156 = 6 u
6 u = 546

1 u = 546 ÷ 6 = 91

Number of stamps that Gillian had at first
= 4 boxes + 1 u
= (4 x 78) + 91
= 312 + 91
= 403

Percent that Gillian had less in the end than at first
= ^{403 - 390}₄₀₃ x 100%
≈ 3.2%

Answer(s): 3.2%