The ratio of spirit and water in the two vessels is 5 : 1 and 3 : 7 respectively. In what ratio the liquid of both the vessels should be mixed such that a new mixture containing half spirit and half water is obtained?
The ratio of spirit and water in the two vessels is 5 : 1 and 3 : 7 respectively. In what ratio the liquid of both the vessels should be mixed such that a new mixture containing half spirit and half water is obtained? Correct Answer 3 : 5
Let x litre of the first mixture and y litre of the second mixture are mixed.
Quantity of spirit in x litre of the first mixture = 5x/6
Quantity of spirit in y litre of second mixture = 3y/10
The total quantity of the resultant mixture = (x + y)
Quantity of spirit in (x + y) litre of the resultant mixture = (x + y) /2
5x/6 + 3y/10 = (x + y) /2
⇒ (25x + 9y) /30 = (x + y) /2
⇒ 25x + 9y = 15 × (x + y)
⇒ 25x + 9y = 15x + 15y
⇒ 10x = 6y
⇒ x/y = 3/5
∴ required ratio = 3 : 5
Alternative method :
Concentration of spirit in the first mixture = 5/6
Concentration of spirit in the second mixture = 3/10
Concentration of spirit in the resultant mixture = 1/2
By rule of allegation,
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∴ Required ratio = (1/5) : (1/3) = 3 : 5