Opal made croissants for sale. 55% of the croissants were egg croissants and the rest were chocolate and sardine croissants in the ratio 3 : 2. If a customer bought 75% of the egg croissants and all of the sardine croissants, what percentage of the chocolate croissants must Opal sell for her to maintain the original percentage of egg croissants at first? Leave your answer in decimals and correct to 1 decimal place.

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

	Egg croissants	Chocolate croissants	Sardine croissants	Total croissants
Before	11 u	5.4 u	3.6 u	20 u
Change	- 8.25 u	- 3.15 u	- 3.6 u
After	2.75 u	2.25 u	0	5 u

55% = ⁵⁵₁₀₀ = ¹¹₂₀
75% = ⁷⁵₁₀₀ = ³₄

Total number of croissants = 20 u

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

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

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

Number of egg croissants sold
= 75% x 11 u
= ⁷⁵₁₀₀ x 11 u
= ³₄ x 11 u
= 8.25 u

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

Number of egg croissants left 
= 11 u - 8.25 u
= 2.75 u

To maintain the percentage of the egg croissants in the end, 
55% → 2.75 u
100% → ^2.75₅₅ x 100 = 5 u

Total number of croissants in the end to maintain the original percentage of egg croissants = 5 u

Number of chocolate croissants left
= 5 u - 2.75 u
= 2.25 u

Number of chocolate croissants that Opal must sell to maintain the original percentage of egg croissants
= 5.4 u - 2.25 u
= 3.15 u

Percentage of the chocolate croissants that Opal must sell
= ^3.15_5.4 x 100%
= 58.3%

Answer(s): 58.3%