A chemical solution contains 30% water and 70% Alkali

A chemical solution contains 30% water and 70% Alkali. What quantity of water should be added to 6 litre of solution so that water content becomes 40%?
(a) 900 ml
(b) 1000 ml
(c) 500 ml
(d) 700 ml

Anurag Mishra Professor Asked on 2nd April 2016 in Maths.
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1 Answer(s)

Answer: (b) 1000 ml

Solution:-

Let X liter of water is added to the solution.
Then, Total quantity of solution= (6 + x) litre
Quantity of water =  (1.8 + X) litre
concentration of water = 40%

Quantity of water in 6 litre solution = 6 x 30/100
= 1.8 litre

Therefore,
(6 + x) x 40/100 = 1.8 + X
(6 + X) x 2/5 = 1.8 + X
2 (6 + X) = 5 (1.8 + X)
12 + 2 X = 9 + 5 X
3 X = 3
X = 1 litre
As we know that 1 litre = 1000 ml

Then, the quantity of water should be added 1000 ml.

Hence, the correct answer is option (b) 1000 ml.
Anurag Mishra Professor Answered on 3rd April 2016.
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