Emily, Abi and Cindy had 1386 pens. Abi won some of the pens from Emily and as a result, Abi's pens increased by 50%. Cindy then won some pens from Abi and Cindy's pens increased by 75%. Finally, Cindy lost some of her pens to Emily and Emily's pens increased by 20%. In the end, they realised that they each had an equal number of pens. How many percent less did Emily have in the end than what she had at first? Correct your answer to 1 decimal place.

Emily	Abi	Cindy
1386
	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 = 1386

1 group = 1386 ÷ 3 = 462

1 group = 6 boxes
6 boxes = 462

1 box = 462 ÷ 6 = 77

1 group + 1 box = 7 p
462 + 77 = 7 p
7 p = 539

1 p = 539 ÷ 7 = 77

3 p = 3 x 77 = 231

1 group + 3 p = 3 u
462 + 231 = 3 u
3 u = 693

1 u = 693 ÷ 3 = 231

Number of pens that Emily had at first
= 5 boxes + 1 u
= (5 x 77) + 231
= 385 + 231
= 616

Percent that Emily had less in the end than at first
= ^{616 - 462}₆₁₆ x 100%
≈ 25.0%

Answer(s): 25.0%