Shannon made muffins for sale. 50% of the muffins were chicken muffins and the rest were kaya and sardine muffins in the ratio 4 : 1. If a customer bought 70% of the chicken muffins and all of the sardine muffins, what percentage of the kaya muffins must Shannon sell for her to maintain the original percentage of chicken muffins at first? Leave your answer in decimals and correct to 1 decimal place.

Chicken muffins	Kaya muffins	Sardine muffins
1 u	1 u
	0.8 u	0.2 u

	Chicken muffins	Kaya muffins	Sardine muffins	Total muffins
Before	1 u	0.8 u	0.2 u	2 u
Change	- 0.7 u	- 0.5 u	- 0.2 u
After	0.3 u	0.3 u	0	0.6 u

50% = ⁵⁰₁₀₀ = ¹₂
70% = ⁷⁰₁₀₀ = ⁷₁₀

Total number of muffins = 2 u

Number of kaya and sardine muffins
= 2 u - 1 u
= 1 u

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

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

Number of chicken muffins sold
= 70% x 1 u
= ⁷⁰₁₀₀ x 1 u
= ⁷₁₀ x 1 u
= 0.7 u

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

Number of chicken muffins left 
= 1 u - 0.7 u
= 0.3 u

To maintain the percentage of the chicken muffins in the end, 
50% → 0.3 u
100% → ^0.3₅₀ x 100 = 0.6 u

Total number of muffins in the end to maintain the original percentage of chicken muffins = 0.6 u

Number of kaya muffins left
= 0.6 u - 0.3 u
= 0.3 u

Number of kaya muffins that Shannon must sell to maintain the original percentage of chicken muffins
= 0.8 u - 0.3 u
= 0.5 u

Percentage of the kaya muffins that Shannon must sell
= ^0.5_0.8 x 100%
= 62.5%

Answer(s): 62.5%