Anna made croissants for sale. 55% of the croissants were sardine croissants and the rest were chocolate and chicken croissants in the ratio 3 : 2. If a customer bought 60% of the sardine croissants and all of the chicken croissants, what percentage of the chocolate croissants must Anna sell for her to maintain the original percentage of sardine croissants at first? Leave your answer in decimals and correct to 1 decimal place.

Sardine croissants	Chocolate croissants	Chicken croissants
11 u	9 u
	5.4 u	3.6 u

	Sardine croissants	Chocolate croissants	Chicken croissants	Total croissants
Before	11 u	5.4 u	3.6 u	20 u
Change	- 6.6 u	- 1.8 u	- 3.6 u
After	4.4 u	3.6 u	0	8 u

55% = ⁵⁵₁₀₀ = ¹¹₂₀
60% = ⁶⁰₁₀₀ = ³₅

Total number of croissants = 20 u

Number of chocolate and chicken croissants
= 20 u - 11 u
= 9 u

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

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

Number of sardine croissants sold
= 60% x 11 u
= ⁶⁰₁₀₀ x 11 u
= ³₅ x 11 u
= 6.6 u

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

Number of sardine croissants left 
= 11 u - 6.6 u
= 4.4 u

To maintain the percentage of the sardine croissants in the end, 
55% → 4.4 u
100% → ^4.4₅₅ x 100 = 8 u

Total number of croissants in the end to maintain the original percentage of sardine croissants = 8 u

Number of chocolate croissants left
= 8 u - 4.4 u
= 3.6 u

Number of chocolate croissants that Anna must sell to maintain the original percentage of sardine croissants
= 5.4 u - 3.6 u
= 1.8 u

Percentage of the chocolate croissants that Anna must sell
= ^1.8_5.4 x 100%
= 33.3%

Answer(s): 33.3%