1. A container filled with liquid containing 4 parts of water and 6 parts of milk. How much of mixture must be drawn off and filled with water so that the mixture contains half milk and half water.

A. 1/4 B. 1/3 C. 1/6 D. 1/5

Answer Answer: Option C Explanation: Let water = 40ltr and milk is 60ltr.
Water = 40 – x*(2/5) + x and milk = 60 – x*(3/5) [x is the amount of mixture taken out] Equate both the equation, we get x = 50/3.
Now, mixture drawn off = (50/3)/100 = 1/6

2. A painter mixes blue paint with white paint so that the mixture contains 10% blue paint.In a mixture of 40 litres paint how many litres blue paint should be added so that the mixture contains 20% of blue paint?

A. 2.5 litres B. 4litres C. 5litres D. 2 litres

Answer Answer: Option C Explanation: Percentage of blue point, in pure Blue point =100%
So, 8 : 1
Since 8 = 40
1 = 5 liters

3. Two cans P and Q contains milk and water in the ratio of 3:2 and 7:3 respectively. The ratio in which these two cans be mixed so as to get a new mixture containing milk and water in the ratio 7:4.

A. 4:7 B. 7:3 C. 7:4 D. 7:5

Answer Answer: Option C Explanation: Milk in 1st can = 3/5 and water = 2/5. Similarly in second can milk = 7/10 and water = 3/10.
Take the ratio = K:1
(3k/5 + 7/10)/(2k/5 + 3/10) = 7/4
Solve for k, we get k = 7/4. So the ratio is 7:4

4. Two bottles A and B contain diluted sulphuric acid. In a bottle A, the amount of water is double the amount of acid while in bottle B, The amount of acid is 3 times that of water. How much mixture should be taken from each bottle in order to prepare 5 litres diluted sulphuric acid containing equal amount of acid and water?

A. 1,4 B. 4,1 C. 3,2 D. 2,3

Answer Answer: Option C Explanation: In a bottle a ratio acid : water = 1:2, B = 3:1
Mixture 1:1, required acid = 1/2
1/3 3/4
............1/2.............
1/4 1/6

5. A vessel is filled with liquid, 3 parts of which are water and 5 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. 1/3 B. 1/4 C. 1/5 D. 1/7

Answer Answer: Option C Explanation: suppose the vessel initially contains 8 litres of liquid.
Let x litres of this liquid be replaced with water.
Quantity of water in new mixture = (3 - 3x/8 +x) litres.
Quantity of syrup in new mixture = (5 - 5x/8) litres
Therefore (3 - 3x/8 + x) = (5 - 5x/8) => 5x +24 = 40 - 5x => 10x =16 => x = 8/5.
So, part of the mixture replaced = (8/5*1/8) = 1/5.