Yoko made buns for sale. 60% of the buns were lotus paste buns and the rest were chicken and beef buns in the ratio 4 : 1. If a customer bought 65% of the lotus paste buns and all of the beef buns, what percentage of the chicken buns must Yoko sell for her to maintain the original percentage of lotus paste buns at first? Leave your answer in decimals and correct to 1 decimal place.

Lotus paste buns	Chicken buns	Beef buns
3 u	2 u
	1.6 u	0.4 u

	Lotus paste buns	Chicken buns	Beef buns	Total buns
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 buns = 5 u

Number of chicken and beef buns
= 5 u - 3 u
= 2 u

Number of chicken buns at first
= ⁴₅ x 2 u
= 1.6 u

Number of beef buns at first
= 2 u - 1.6 u
= 0.4 u

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

Number of beef buns sold
= ¹₅ x 2 u
= 0.4 u

Number of lotus paste buns left 
= 3 u - 1.95 u
= 1.05 u

To maintain the percentage of the lotus paste 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 lotus paste buns = 1.75 u

Number of chicken buns left
= 1.75 u - 1.05 u
= 0.7 u

Number of chicken buns that Yoko must sell to maintain the original percentage of lotus paste buns
= 1.6 u - 0.7 u
= 0.9 u

Percentage of the chicken buns that Yoko must sell
= ^0.9_1.6 x 100%
= 56.3%

Answer(s): 56.3%