Usha made buns for sale. 50% of the buns were mushroom buns and the rest were egg and chocolate buns in the ratio 3 : 2. If a customer bought 75% of the mushroom buns and all of the chocolate buns, what percentage of the egg buns must Usha sell for her to maintain the original percentage of mushroom buns at first? Leave your answer in decimals and correct to 1 decimal place.

Mushroom buns	Egg buns	Chocolate buns
1 u	1 u
	0.6 u	0.4 u

	Mushroom buns	Egg buns	Chocolate buns	Total buns
Before	1 u	0.6 u	0.4 u	2 u
Change	- 0.75 u	- 0.35 u	- 0.4 u
After	0.25 u	0.25 u	0	0.5 u

50% = ⁵⁰₁₀₀ = ¹₂
75% = ⁷⁵₁₀₀ = ³₄

Total number of buns = 2 u

Number of egg and chocolate buns
= 2 u - 1 u
= 1 u

Number of egg buns at first
= ³₅ x 1 u
= 0.6 u

Number of chocolate buns at first
= 1 u - 0.6 u
= 0.4 u

Number of mushroom buns sold
= 75% x 1 u
= ⁷⁵₁₀₀ x 1 u
= ³₄ x 1 u
= 0.75 u

Number of chocolate buns sold
= ²₅ x 1 u
= 0.4 u

Number of mushroom buns left 
= 1 u - 0.75 u
= 0.25 u

To maintain the percentage of the mushroom buns in the end, 
50% → 0.25 u
100% → ^0.25₅₀ x 100 = 0.5 u

Total number of buns in the end to maintain the original percentage of mushroom buns = 0.5 u

Number of egg buns left
= 0.5 u - 0.25 u
= 0.25 u

Number of egg buns that Usha must sell to maintain the original percentage of mushroom buns
= 0.6 u - 0.25 u
= 0.35 u

Percentage of the egg buns that Usha must sell
= ^0.35_0.6 x 100%
= 58.3%

Answer(s): 58.3%