Roshel made sandwiches for sale. 40% of the sandwiches were egg sandwiches and the rest were chocolate and chicken sandwiches in the ratio 3 : 1. If a customer bought 65% of the egg sandwiches and all of the chicken sandwiches, what percentage of the chocolate sandwiches must Roshel sell for her to maintain the original percentage of egg sandwiches at first? Leave your answer in decimals and correct to 1 decimal place.

Egg sandwiches	Chocolate sandwiches	Chicken sandwiches
2 u	3 u
	2.25 u	0.75 u

	Egg sandwiches	Chocolate sandwiches	Chicken sandwiches	Total sandwiches
Before	2 u	2.25 u	0.75 u	5 u
Change	- 1.3 u	- 1.2 u	- 0.75 u
After	0.7 u	1.05 u	0	1.75 u

40% = ⁴⁰₁₀₀ = ²₅
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of sandwiches = 5 u

Number of chocolate and chicken sandwiches
= 5 u - 2 u
= 3 u

Number of chocolate sandwiches at first
= ³₄ x 3 u
= 2.25 u

Number of chicken sandwiches at first
= 3 u - 2.25 u
= 0.75 u

Number of egg sandwiches sold
= 65% x 2 u
= ⁶⁵₁₀₀ x 2 u
= ¹³₂₀ x 2 u
= 1.3 u

Number of chicken sandwiches sold
= ¹₄ x 3 u
= 0.75 u

Number of egg sandwiches left 
= 2 u - 1.3 u
= 0.7 u

To maintain the percentage of the egg sandwiches in the end, 
40% → 0.7 u
100% → ^0.7₄₀ x 100 = 1.75 u

Total number of sandwiches in the end to maintain the original percentage of egg sandwiches = 1.75 u

Number of chocolate sandwiches left
= 1.75 u - 0.7 u
= 1.05 u

Number of chocolate sandwiches that Roshel must sell to maintain the original percentage of egg sandwiches
= 2.25 u - 1.05 u
= 1.2 u

Percentage of the chocolate sandwiches that Roshel must sell
= ^1.2_2.25 x 100%
= 53.3%

Answer(s): 53.3%