Ivory made buns for sale. 55% of the buns were egg buns and the rest were curry and chicken buns in the ratio 2 : 1. If a customer bought 85% of the egg buns and all of the chicken buns, what percentage of the curry buns must Ivory sell for her to maintain the original percentage of egg buns at first? Leave your answer in decimals and correct to 1 decimal place.

Egg buns	Curry buns	Chicken buns
11 u	9 u
	6 u	3 u

	Egg buns	Curry buns	Chicken buns	Total buns
Before	11 u	6 u	3 u	20 u
Change	- 9.35 u	- 4.65 u	- 3 u
After	1.65 u	1.35 u	0	3 u

55% = ⁵⁵₁₀₀ = ¹¹₂₀
85% = ⁸⁵₁₀₀ = ¹⁷₂₀

Total number of buns = 20 u

Number of curry and chicken buns
= 20 u - 11 u
= 9 u

Number of curry buns at first
= ²₃ x 9 u
= 6 u

Number of chicken buns at first
= 9 u - 6 u
= 3 u

Number of egg buns sold
= 85% x 11 u
= ⁸⁵₁₀₀ x 11 u
= ¹⁷₂₀ x 11 u
= 9.35 u

Number of chicken buns sold
= ¹₃ x 9 u
= 3 u

Number of egg buns left 
= 11 u - 9.35 u
= 1.65 u

To maintain the percentage of the egg buns in the end, 
55% → 1.65 u
100% → ^1.65₅₅ x 100 = 3 u

Total number of buns in the end to maintain the original percentage of egg buns = 3 u

Number of curry buns left
= 3 u - 1.65 u
= 1.35 u

Number of curry buns that Ivory must sell to maintain the original percentage of egg buns
= 6 u - 1.35 u
= 4.65 u

Percentage of the curry buns that Ivory must sell
= ^4.65₆ x 100%
= 77.5%

Answer(s): 77.5%