Gabby made muffins for sale. 45% of the muffins were egg muffins and the rest were kaya and mushroom muffins in the ratio 4 : 1. If a customer bought 85% of the egg muffins and all of the mushroom muffins, what percentage of the kaya muffins must Gabby sell for her to maintain the original percentage of egg muffins at first? Leave your answer in decimals and correct to 1 decimal place.

Egg muffins	Kaya muffins	Mushroom muffins
9 u	11 u
	8.8 u	2.2 u

	Egg muffins	Kaya muffins	Mushroom muffins	Total muffins
Before	9 u	8.8 u	2.2 u	20 u
Change	- 7.65 u	- 7.15 u	- 2.2 u
After	1.35 u	1.65 u	0	3 u

45% = ⁴⁵₁₀₀ = ⁹₂₀
85% = ⁸⁵₁₀₀ = ¹⁷₂₀

Total number of muffins = 20 u

Number of kaya and mushroom muffins
= 20 u - 9 u
= 11 u

Number of kaya muffins at first
= ⁴₅ x 11 u
= 8.8 u

Number of mushroom muffins at first
= 11 u - 8.8 u
= 2.2 u

Number of egg muffins sold
= 85% x 9 u
= ⁸⁵₁₀₀ x 9 u
= ¹⁷₂₀ x 9 u
= 7.65 u

Number of mushroom muffins sold
= ¹₅ x 11 u
= 2.2 u

Number of egg muffins left 
= 9 u - 7.65 u
= 1.35 u

To maintain the percentage of the egg muffins in the end, 
45% → 1.35 u
100% → ^1.35₄₅ x 100 = 3 u

Total number of muffins in the end to maintain the original percentage of egg muffins = 3 u

Number of kaya muffins left
= 3 u - 1.35 u
= 1.65 u

Number of kaya muffins that Gabby must sell to maintain the original percentage of egg muffins
= 8.8 u - 1.65 u
= 7.15 u

Percentage of the kaya muffins that Gabby must sell
= ^7.15_8.8 x 100%
= 81.3%

Answer(s): 81.3%