Pamela, Xandra and Shannon had 684 erasers. Xandra won some of the erasers from Pamela and as a result, Xandra's erasers increased by 50%. Shannon then won some erasers from Xandra and Shannon's erasers increased by 75%. Finally, Shannon lost some of her erasers to Pamela and Pamela's erasers increased by 20%. In the end, they realised that they each had an equal number of erasers. How many percent less did Pamela have in the end than what she had at first? Correct your answer to 1 decimal place.

Pamela	Xandra	Shannon
684
	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 = 684

1 group = 684 ÷ 3 = 228

1 group = 6 boxes
6 boxes = 228

1 box = 228 ÷ 6 = 38

1 group + 1 box = 7 p
228 + 38 = 7 p
7 p = 266

1 p = 266 ÷ 7 = 38

3 p = 3 x 38 = 114

1 group + 3 p = 3 u
228 + 114 = 3 u
3 u = 342

1 u = 342 ÷ 3 = 114

Number of erasers that Pamela had at first
= 5 boxes + 1 u
= (5 x 38) + 114
= 190 + 114
= 304

Percent that Pamela had less in the end than at first
= ^{304 - 228}₃₀₄ x 100%
≈ 25.0%

Answer(s): 25.0%