Roshel, Abi and Tiffany had 702 erasers. Abi won some of the erasers from Roshel and as a result, Abi's erasers increased by 50%. Tiffany then won some erasers from Abi and Tiffany's erasers increased by 40%. Finally, Tiffany lost some of her erasers to Roshel and Roshel's erasers increased by 20%. In the end, they realised that they each had an equal number of erasers. How many percent less did Roshel have in the end than what she had at first? Correct your answer to 1 decimal place.

Roshel	Abi	Tiffany
702
	2 u
- 1 u	+ 1 u
	3 u
		5 p
	- 2 p	+ 2 p
		7 p
5 boxes
+ 1 box		- 1 box
6 boxes
1 group	1 group	1 group

50% = ⁵⁰₁₀₀ = ¹₂
40% = ⁴⁰₁₀₀ = ²₅
20% = ²⁰₁₀₀ = ¹₅

Working backwards.

3 groups = 702

1 group = 702 ÷ 3 = 234

1 group = 6 boxes
6 boxes = 234

1 box = 234 ÷ 6 = 39

1 group + 1 box = 7 p
234 + 39 = 7 p
7 p = 273

1 p = 273 ÷ 7 = 39

2 p = 2 x 39 = 78

1 group + 2 p = 3 u
234 + 78 = 3 u
3 u = 312

1 u = 312 ÷ 3 = 104

Number of erasers that Roshel had at first
= 5 boxes + 1 u
= (5 x 39) + 104
= 195 + 104
= 299

Percent that Roshel had less in the end than at first
= ^{299 - 234}₂₉₉ x 100%
≈ 21.7%

Answer(s): 21.7%