Winnie, Zara and Jen had 1134 erasers. Zara won some of the erasers from Winnie and as a result, Zara's erasers increased by 50%. Jen then won some erasers from Zara and Jen's erasers increased by 40%. Finally, Jen lost some of her erasers to Winnie and Winnie's erasers increased by 20%. In the end, they realised that they each had an equal number of erasers. How many percent less did Winnie have in the end than what she had at first? Correct your answer to 1 decimal place.

Winnie	Zara	Jen
1134
	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 = 1134

1 group = 1134 ÷ 3 = 378

1 group = 6 boxes
6 boxes = 378

1 box = 378 ÷ 6 = 63

1 group + 1 box = 7 p
378 + 63 = 7 p
7 p = 441

1 p = 441 ÷ 7 = 63

2 p = 2 x 63 = 126

1 group + 2 p = 3 u
378 + 126 = 3 u
3 u = 504

1 u = 504 ÷ 3 = 168

Number of erasers that Winnie had at first
= 5 boxes + 1 u
= (5 x 63) + 168
= 315 + 168
= 483

Percent that Winnie had less in the end than at first
= ^{483 - 378}₄₈₃ x 100%
≈ 21.7%

Answer(s): 21.7%