Erika made muffins for sale. 50% of the muffins were beef muffins and the rest were kaya and lotus paste muffins in the ratio 3 : 1. If a customer bought 65% of the beef muffins and all of the lotus paste muffins, what percentage of the kaya muffins must Erika sell for her to maintain the original percentage of beef muffins at first? Leave your answer in decimals and correct to 1 decimal place.

Beef muffins	Kaya muffins	Lotus paste muffins
1 u	1 u
	0.75 u	0.25 u

	Beef muffins	Kaya muffins	Lotus paste muffins	Total muffins
Before	1 u	0.75 u	0.25 u	2 u
Change	- 0.65 u	- 0.4 u	- 0.25 u
After	0.35 u	0.35 u	0	0.7 u

50% = ⁵⁰₁₀₀ = ¹₂
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of muffins = 2 u

Number of kaya and lotus paste muffins
= 2 u - 1 u
= 1 u

Number of kaya muffins at first
= ³₄ x 1 u
= 0.75 u

Number of lotus paste muffins at first
= 1 u - 0.75 u
= 0.25 u

Number of beef muffins sold
= 65% x 1 u
= ⁶⁵₁₀₀ x 1 u
= ¹³₂₀ x 1 u
= 0.65 u

Number of lotus paste muffins sold
= ¹₄ x 1 u
= 0.25 u

Number of beef muffins left 
= 1 u - 0.65 u
= 0.35 u

To maintain the percentage of the beef muffins in the end, 
50% → 0.35 u
100% → ^0.35₅₀ x 100 = 0.7 u

Total number of muffins in the end to maintain the original percentage of beef muffins = 0.7 u

Number of kaya muffins left
= 0.7 u - 0.35 u
= 0.35 u

Number of kaya muffins that Erika must sell to maintain the original percentage of beef muffins
= 0.75 u - 0.35 u
= 0.4 u

Percentage of the kaya muffins that Erika must sell
= ^0.4_0.75 x 100%
= 53.3%

Answer(s): 53.3%