Kathy made croissants for sale. 55% of the croissants were beef croissants and the rest were mushroom and curry croissants in the ratio 3 : 2. If a customer bought 65% of the beef croissants and all of the curry croissants, what percentage of the mushroom croissants must Kathy sell for her to maintain the original percentage of beef croissants at first? Leave your answer in decimals and correct to 1 decimal place.

Beef croissants	Mushroom croissants	Curry croissants
11 u	9 u
	5.4 u	3.6 u

	Beef croissants	Mushroom croissants	Curry croissants	Total croissants
Before	11 u	5.4 u	3.6 u	20 u
Change	- 7.15 u	- 2.25 u	- 3.6 u
After	3.85 u	3.15 u	0	7 u

55% = ⁵⁵₁₀₀ = ¹¹₂₀
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of croissants = 20 u

Number of mushroom and curry croissants
= 20 u - 11 u
= 9 u

Number of mushroom croissants at first
= ³₅ x 9 u
= 5.4 u

Number of curry croissants at first
= 9 u - 5.4 u
= 3.6 u

Number of beef croissants sold
= 65% x 11 u
= ⁶⁵₁₀₀ x 11 u
= ¹³₂₀ x 11 u
= 7.15 u

Number of curry croissants sold
= ²₅ x 9 u
= 3.6 u

Number of beef croissants left 
= 11 u - 7.15 u
= 3.85 u

To maintain the percentage of the beef croissants in the end, 
55% → 3.85 u
100% → ^3.85₅₅ x 100 = 7 u

Total number of croissants in the end to maintain the original percentage of beef croissants = 7 u

Number of mushroom croissants left
= 7 u - 3.85 u
= 3.15 u

Number of mushroom croissants that Kathy must sell to maintain the original percentage of beef croissants
= 5.4 u - 3.15 u
= 2.25 u

Percentage of the mushroom croissants that Kathy must sell
= ^2.25_5.4 x 100%
= 41.7%

Answer(s): 41.7%