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

Chocolate muffins	Sardine muffins	Egg muffins
9 u	11 u
	8.8 u	2.2 u

	Chocolate muffins	Sardine muffins	Egg 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 sardine and egg muffins
= 20 u - 9 u
= 11 u

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

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

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

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

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

To maintain the percentage of the chocolate 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 chocolate muffins = 3 u

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

Number of sardine muffins that Jaslyn must sell to maintain the original percentage of chocolate muffins
= 8.8 u - 1.65 u
= 7.15 u

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

Answer(s): 81.3%