Fiona made buns for sale. 60% of the buns were kaya buns and the rest were lotus paste and egg buns in the ratio 3 : 2. If a customer bought 65% of the kaya buns and all of the egg buns, what percentage of the lotus paste buns must Fiona 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	Lotus paste buns	Egg buns
3 u	2 u
	1.2 u	0.8 u

	Kaya buns	Lotus paste buns	Egg buns	Total buns
Before	3 u	1.2 u	0.8 u	5 u
Change	- 1.95 u	- 0.5 u	- 0.8 u
After	1.05 u	0.7 u	0	1.75 u

60% = ⁶⁰₁₀₀ = ³₅
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of buns = 5 u

Number of lotus paste and egg buns
= 5 u - 3 u
= 2 u

Number of lotus paste buns at first
= ³₅ x 2 u
= 1.2 u

Number of egg buns at first
= 2 u - 1.2 u
= 0.8 u

Number of kaya buns sold
= 65% x 3 u
= ⁶⁵₁₀₀ x 3 u
= ¹³₂₀ x 3 u
= 1.95 u

Number of egg buns sold
= ²₅ x 2 u
= 0.8 u

Number of kaya buns left 
= 3 u - 1.95 u
= 1.05 u

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

Total number of buns in the end to maintain the original percentage of kaya buns = 1.75 u

Number of lotus paste buns left
= 1.75 u - 1.05 u
= 0.7 u

Number of lotus paste buns that Fiona must sell to maintain the original percentage of kaya buns
= 1.2 u - 0.7 u
= 0.5 u

Percentage of the lotus paste buns that Fiona must sell
= ^0.5_1.2 x 100%
= 41.7%

Answer(s): 41.7%