Tina made croissants for sale. 60% of the croissants were chocolate croissants and the rest were curry and sardine croissants in the ratio 4 : 1. If a customer bought 65% of the chocolate croissants and all of the sardine croissants, what percentage of the curry croissants must Tina sell for her to maintain the original percentage of chocolate croissants at first? Leave your answer in decimals and correct to 1 decimal place.

Chocolate croissants	Curry croissants	Sardine croissants
3 u	2 u
	1.6 u	0.4 u

	Chocolate croissants	Curry croissants	Sardine croissants	Total croissants
Before	3 u	1.6 u	0.4 u	5 u
Change	- 1.95 u	- 0.9 u	- 0.4 u
After	1.05 u	0.7 u	0	1.75 u

60% = ⁶⁰₁₀₀ = ³₅
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of croissants = 5 u

Number of curry and sardine croissants
= 5 u - 3 u
= 2 u

Number of curry croissants at first
= ⁴₅ x 2 u
= 1.6 u

Number of sardine croissants at first
= 2 u - 1.6 u
= 0.4 u

Number of chocolate croissants sold
= 65% x 3 u
= ⁶⁵₁₀₀ x 3 u
= ¹³₂₀ x 3 u
= 1.95 u

Number of sardine croissants sold
= ¹₅ x 2 u
= 0.4 u

Number of chocolate croissants left 
= 3 u - 1.95 u
= 1.05 u

To maintain the percentage of the chocolate croissants in the end, 
60% → 1.05 u
100% → ^1.05₆₀ x 100 = 1.75 u

Total number of croissants in the end to maintain the original percentage of chocolate croissants = 1.75 u

Number of curry croissants left
= 1.75 u - 1.05 u
= 0.7 u

Number of curry croissants that Tina must sell to maintain the original percentage of chocolate croissants
= 1.6 u - 0.7 u
= 0.9 u

Percentage of the curry croissants that Tina must sell
= ^0.9_1.6 x 100%
= 56.3%

Answer(s): 56.3%