Abi, Penelope and Tiffany had 936 stickers. Penelope won some of the stickers from Abi and as a result, Penelope's stickers increased by 50%. Tiffany then won some stickers from Penelope and Tiffany's stickers increased by 30%. Finally, Tiffany lost some of her stickers to Abi and Abi's stickers increased by 20%. In the end, they realised that they each had an equal number of stickers. How many percent less did Abi have in the end than what she had at first? Correct your answer to 1 decimal place.

Abi	Penelope	Tiffany
936
	2 u
- 1 u	+ 1 u
	3 u
		10 p
	- 3 p	+ 3 p
		13 p
5 boxes
+ 1 box		- 1 box
6 boxes
1 group	1 group	1 group

50% = ⁵⁰₁₀₀ = ¹₂
30% = ³⁰₁₀₀ = ³₁₀
20% = ²⁰₁₀₀ = ¹₅

Working backwards.

3 groups = 936

1 group = 936 ÷ 3 = 312

1 group = 6 boxes
6 boxes = 312

1 box = 312 ÷ 6 = 52

1 group + 1 box = 13 p
312 + 52 = 13 p
13 p = 364

1 p = 364 ÷ 13 = 28

3 p = 3 x 28 = 84

1 group + 3 p = 3 u
312 + 84 = 3 u
3 u = 396

1 u = 396 ÷ 3 = 132

Number of stickers that Abi had at first
= 5 boxes + 1 u
= (5 x 52) + 132
= 260 + 132
= 392

Percent that Abi had less in the end than at first
= ^{392 - 312}₃₉₂ x 100%
≈ 20.4%

Answer(s): 20.4%