Wendy made muffins for sale. 50% of the muffins were mushroom muffins and the rest were kaya and chocolate muffins in the ratio 4 : 1. If a customer bought 65% of the mushroom muffins and all of the chocolate muffins, what percentage of the kaya muffins must Wendy sell for her to maintain the original percentage of mushroom muffins at first? Leave your answer in decimals and correct to 1 decimal place.

Mushroom muffins	Kaya muffins	Chocolate muffins
1 u	1 u
	0.8 u	0.2 u

	Mushroom muffins	Kaya muffins	Chocolate muffins	Total muffins
Before	1 u	0.8 u	0.2 u	2 u
Change	- 0.65 u	- 0.45 u	- 0.2 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 chocolate muffins
= 2 u - 1 u
= 1 u

Number of kaya muffins at first
= ⁴₅ x 1 u
= 0.8 u

Number of chocolate muffins at first
= 1 u - 0.8 u
= 0.2 u

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

Number of chocolate muffins sold
= ¹₅ x 1 u
= 0.2 u

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

To maintain the percentage of the mushroom 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 mushroom muffins = 0.7 u

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

Number of kaya muffins that Wendy must sell to maintain the original percentage of mushroom muffins
= 0.8 u - 0.35 u
= 0.45 u

Percentage of the kaya muffins that Wendy must sell
= ^0.45_0.8 x 100%
= 56.3%

Answer(s): 56.3%