Abi made buns for sale. 55% of the buns were kaya buns and the rest were mushroom and lotus paste buns in the ratio 3 : 2. If a customer bought 75% of the kaya buns and all of the lotus paste buns, what percentage of the mushroom buns must Abi sell for her to maintain the original percentage of kaya buns at first? Leave your answer in decimals and correct to 1 decimal place.

Kaya buns	Mushroom buns	Lotus paste buns
11 u	9 u
	5.4 u	3.6 u

	Kaya buns	Mushroom buns	Lotus paste buns	Total buns
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 buns = 20 u

Number of mushroom and lotus paste buns
= 20 u - 11 u
= 9 u

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

Number of lotus paste buns at first
= 9 u - 5.4 u
= 3.6 u

Number of kaya buns sold
= 75% x 11 u
= ⁷⁵₁₀₀ x 11 u
= ³₄ x 11 u
= 8.25 u

Number of lotus paste buns sold
= ²₅ x 9 u
= 3.6 u

Number of kaya buns left 
= 11 u - 8.25 u
= 2.75 u

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

Total number of buns in the end to maintain the original percentage of kaya buns = 5 u

Number of mushroom buns left
= 5 u - 2.75 u
= 2.25 u

Number of mushroom buns that Abi must sell to maintain the original percentage of kaya buns
= 5.4 u - 2.25 u
= 3.15 u

Percentage of the mushroom buns that Abi must sell
= ^3.15_5.4 x 100%
= 58.3%

Answer(s): 58.3%