Penelope made sandwiches for sale. 60% of the sandwiches were egg sandwiches and the rest were curry and mushroom sandwiches in the ratio 4 : 1. If a customer bought 65% of the egg sandwiches and all of the mushroom sandwiches, what percentage of the curry sandwiches must Penelope 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	Curry sandwiches	Mushroom sandwiches
3 u	2 u
	1.6 u	0.4 u

	Egg sandwiches	Curry sandwiches	Mushroom sandwiches	Total sandwiches
Before	3 u	1.6 u	0.4 u	5 u
Change	- 1.95 u	- 0.9 u	- 0.4 u
After	1.05 u	0.7 u	0	1.75 u

60% = ⁶⁰₁₀₀ = ³₅
65% = ⁶⁵₁₀₀ = ¹³₂₀

Total number of sandwiches = 5 u

Number of curry and mushroom sandwiches
= 5 u - 3 u
= 2 u

Number of curry sandwiches at first
= ⁴₅ x 2 u
= 1.6 u

Number of mushroom sandwiches at first
= 2 u - 1.6 u
= 0.4 u

Number of egg sandwiches sold
= 65% x 3 u
= ⁶⁵₁₀₀ x 3 u
= ¹³₂₀ x 3 u
= 1.95 u

Number of mushroom sandwiches sold
= ¹₅ x 2 u
= 0.4 u

Number of egg sandwiches left 
= 3 u - 1.95 u
= 1.05 u

To maintain the percentage of the egg sandwiches in the end, 
60% → 1.05 u
100% → ^1.05₆₀ 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 curry sandwiches left
= 1.75 u - 1.05 u
= 0.7 u

Number of curry sandwiches that Penelope must sell to maintain the original percentage of egg sandwiches
= 1.6 u - 0.7 u
= 0.9 u

Percentage of the curry sandwiches that Penelope must sell
= ^0.9_1.6 x 100%
= 56.3%

Answer(s): 56.3%