Jen, Emily and Barbara had 1242 cards. Emily won some of the cards from Jen and as a result, Emily's cards increased by 25%. Barbara then won some cards from Emily and Barbara's cards increased by 50%. Finally, Barbara lost some of her cards to Jen and Jen's cards increased by 20%. In the end, they realised that they each had an equal number of cards. How many percent less did Jen have in the end than what she had at first? Correct your answer to 1 decimal place.

Jen	Emily	Barbara
1242
	4 u
- 1 u	+ 1 u
	5 u
		2 p
	- 1 p	+ 1 p
		3 p
5 boxes
+ 1 box		- 1 box
6 boxes
1 group	1 group	1 group

25% = ²⁵₁₀₀ = ¹₄
50% = ⁵⁰₁₀₀ = ¹₂
20% = ²⁰₁₀₀ = ¹₅

Working backwards.

3 groups = 1242

1 group = 1242 ÷ 3 = 414

1 group = 6 boxes
6 boxes = 414

1 box = 414 ÷ 6 = 69

1 group + 1 box = 3 p
414 + 69 = 3 p
3 p = 483

1 p = 483 ÷ 3 = 161

1 p = 1 x 161 = 161

1 group + 1 p = 5 u
414 + 161 = 5 u
5 u = 575

1 u = 575 ÷ 5 = 115

Number of cards that Jen had at first
= 5 boxes + 1 u
= (5 x 69) + 115
= 345 + 115
= 460

Percent that Jen had less in the end than at first
= ^{460 - 414}₄₆₀ x 100%
≈ 10.0%

Answer(s): 10.0%