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1) A vessel contains 2 liquids A & B in the ratio of 7:5.When 10 litres of mixture are drawn , the vessel is filled with B, the ratio now becomes 7:10.How many litres of liquid A the vessel initially had?A) 19.83 B) 19.2 C) 2.88 D) 2.83
Answer & Explanation
Answer: 19.83 (Suppose the vessel initially contain 7x litres & 5x litres of A & B respectively
Quantity of A left = (7x -((7/12)*10)) = 7x -(70/12)
Quantity of B left = (5x -((5/12)*10)) = 5x - (50/12)
(7x -(70/12))/(5x - (50/12)+10) = 7/10
420x -350 = 210x +245
x = 2.83 litres
Liquid A in the vessel initially was 19.83 litres
)
2) A container contains 20 litres of milk. From this container 2 litres of milk was taken out and replaced by water. This process was repeated further 4 times. How much milk is now contained by the container?A) 13.25 B) 13.12 C) 13.15 D) 13.57
Answer & Explanation
Answer: 13.12 (Amount of milk left after 4 operations = 20( 1 - 2/20)4 litres =20 * 9/10 * 9/10 *9/10 *9/10 = 13.122 litres)
3) A mixture of 30kg of spirit and water contains 10% water.How much water must be added to the mixture to raise the percentage of water to 40%?
A) 10 B) 5 C) 12 D) 15
Answer & Explanation
Answer: 15 (Water in the given mix is (10/100 * 30) kg = 3kg & spirit is 27kg.
Let x kg be the water be added .Then
100 *((x+3)/(30+x)) = 40
3x = 45 & x= 15kg
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4) 747 ml of mixture contains milk & water in the ratio 7:2. How much more water is to be added to get a new mixture containing the milk and water in the ratio of 7:5?A) 250 B) 249 C) 253 D) 252
Answer & Explanation
Answer: 249 (Milk = (747 * 7/9) = 581 ml. Water = (747 - 581) = 166 ml.
Let the water to be added be x ml.
581/ (166 +x) = 7/5
x = 249 ml)
5) A container is filled with liquid, 3 parts of which are water and 6 parts syrup. How much of the mixture must be drawn off and replaced with water so that the mixture may be half water and half syrup?A) 1/4 B) 1/2 C) 1/3 D) 1/5
Answer & Explanation
Answer: 1/4 (Suppose the vessel initially contains 9 litres of liquid.
Let x litres of this liquid be replaced with water.
Quantity of water in new mixture = 3 - 3x/9 + x litres
Quantity of syrup in new mixture = 6 -6x/9 litres
3 - 3x/9 + x = 6 - 6x/9
There fore, 12x = 27 .x = 27/12
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So, part of the mixture replaced = (27/12 * 1/9) = 1/4
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