Abi, Sarah and Shiyun had 738 erasers. Sarah won some of the erasers from Abi and as a result, Sarah's erasers increased by 50%. Shiyun then won some erasers from Sarah and Shiyun's erasers increased by 75%. Finally, Shiyun lost some of her erasers to Abi and Abi's erasers increased by 20%. In the end, they realised that they each had an equal number of erasers. How many percent less did Abi have in the end than what she had at first? Correct your answer to 1 decimal place.

Abi	Sarah	Shiyun
738
	2 u
- 1 u	+ 1 u
	3 u
		4 p
	- 3 p	+ 3 p
		7 p
5 boxes
+ 1 box		- 1 box
6 boxes
1 group	1 group	1 group

50% = ⁵⁰₁₀₀ = ¹₂
75% = ⁷⁵₁₀₀ = ³₄
20% = ²⁰₁₀₀ = ¹₅

Working backwards.

3 groups = 738

1 group = 738 ÷ 3 = 246

1 group = 6 boxes
6 boxes = 246

1 box = 246 ÷ 6 = 41

1 group + 1 box = 7 p
246 + 41 = 7 p
7 p = 287

1 p = 287 ÷ 7 = 41

3 p = 3 x 41 = 123

1 group + 3 p = 3 u
246 + 123 = 3 u
3 u = 369

1 u = 369 ÷ 3 = 123

Number of erasers that Abi had at first
= 5 boxes + 1 u
= (5 x 41) + 123
= 205 + 123
= 328

Percent that Abi had less in the end than at first
= ^{328 - 246}₃₂₈ x 100%
≈ 25.0%

Answer(s): 25.0%