Nora made muffins for sale. 40% of the muffins were lotus paste muffins and the rest were curry and egg muffins in the ratio 4 : 1. If a customer bought 75% of the lotus paste muffins and all of the egg muffins, what percentage of the curry muffins must Nora sell for her to maintain the original percentage of lotus paste muffins at first? Leave your answer in decimals and correct to 1 decimal place.

Lotus paste muffins	Curry muffins	Egg muffins
2 u	3 u
	2.4 u	0.6 u

	Lotus paste muffins	Curry muffins	Egg muffins	Total muffins
Before	2 u	2.4 u	0.6 u	5 u
Change	- 1.5 u	- 1.65 u	- 0.6 u
After	0.5 u	0.75 u	0	1.25 u

40% = ⁴⁰₁₀₀ = ²₅
75% = ⁷⁵₁₀₀ = ³₄

Total number of muffins = 5 u

Number of curry and egg muffins
= 5 u - 2 u
= 3 u

Number of curry muffins at first
= ⁴₅ x 3 u
= 2.4 u

Number of egg muffins at first
= 3 u - 2.4 u
= 0.6 u

Number of lotus paste muffins sold
= 75% x 2 u
= ⁷⁵₁₀₀ x 2 u
= ³₄ x 2 u
= 1.5 u

Number of egg muffins sold
= ¹₅ x 3 u
= 0.6 u

Number of lotus paste muffins left 
= 2 u - 1.5 u
= 0.5 u

To maintain the percentage of the lotus paste muffins in the end, 
40% → 0.5 u
100% → ^0.5₄₀ x 100 = 1.25 u

Total number of muffins in the end to maintain the original percentage of lotus paste muffins = 1.25 u

Number of curry muffins left
= 1.25 u - 0.5 u
= 0.75 u

Number of curry muffins that Nora must sell to maintain the original percentage of lotus paste muffins
= 2.4 u - 0.75 u
= 1.65 u

Percentage of the curry muffins that Nora must sell
= ^1.65_2.4 x 100%
= 68.8%

Answer(s): 68.8%