Question

A mixture of 40 litres of salt and water contains 70%of salt.how much water must be added to
decrease the salt percentage to 40%?
(a) 40 litres
(b) 30 litres
(c) 20 litres
(d) 2 litres

Answer 1

Your correct option is (b)
AS DONE IN THE ATTACHMENT

Answer 2

Answer:

A mixture of 40 litres of salt and water contains 70%of salt.

then 30 litre water must be added to  decrease the salt percentage to 40%?

Step-by-step explanation:

Mixture of salt & water = 40 litre

Salt % = 70%

70% Salt = (70/100) * 40 = 28 Litre

Water = 40 - 28 = 12 Litre

Let say x litre water is added

then Misxture = 40 + x litre

Salt = 28 Litre

Salt % = 40%

(28/(40+x) )  * 100 = 40

=> 2800 = 1600 + 40x

=> 40x = 1200

=> x = 30

30 litre of water need to be added

option b is correct