Barbara made muffins for sale. 45% of the muffins were egg muffins and the rest were chicken and mushroom muffins in the ratio 4 : 1. If a customer bought 70% of the egg muffins and all of the mushroom muffins, what percentage of the chicken muffins must Barbara 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	Chicken muffins	Mushroom muffins
9 u	11 u
	8.8 u	2.2 u

	Egg muffins	Chicken muffins	Mushroom muffins	Total muffins
Before	9 u	8.8 u	2.2 u	20 u
Change	- 6.3 u	- 5.5 u	- 2.2 u
After	2.7 u	3.3 u	0	6 u

45% = ⁴⁵₁₀₀ = ⁹₂₀
70% = ⁷⁰₁₀₀ = ⁷₁₀

Total number of muffins = 20 u

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

Number of chicken 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
= 70% x 9 u
= ⁷⁰₁₀₀ x 9 u
= ⁷₁₀ x 9 u
= 6.3 u

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

Number of egg muffins left 
= 9 u - 6.3 u
= 2.7 u

To maintain the percentage of the egg muffins in the end, 
45% → 2.7 u
100% → ^2.7₄₅ x 100 = 6 u

Total number of muffins in the end to maintain the original percentage of egg muffins = 6 u

Number of chicken muffins left
= 6 u - 2.7 u
= 3.3 u

Number of chicken muffins that Barbara must sell to maintain the original percentage of egg muffins
= 8.8 u - 3.3 u
= 5.5 u

Percentage of the chicken muffins that Barbara must sell
= ^5.5_8.8 x 100%
= 62.5%

Answer(s): 62.5%