Test Preparation on Mixtures and Allegations For Competitive Exam

A mixture of 150 liters of wine and water contains 20% water. How much more water should be added so that water becomes 25% of the new mixture?

17 liters
215 liters
310 liters
49 liters

Number of liters of water in150 liters of the mixture = 20% of 150 = 20/100 * 150 = 30 liters. P liters of water added to the mixture to make water 25% of the new mixture. Total amount of water becomes (30 + P) and total volume of mixture is (150 + P). (30 + P) = 25/100 * (150 + P) 120 + 4P = 150 + P => P = 10 liters.

A vessel contains 20 liters of a mixture of milk and water in a ratio of 3:2. 10 liters of the mixture are removed and replaced with an equal quantity of pure milk. If the process is repeated once more, find the ratio of milk and water in the final mixture obtained?

19:01
24:07
37:01
42:05

Milk = 3/5 * 20 = 12 liters, water = 8 liters If 10 liters of mixture are removed, amount of milk removed = 6 liters and amount of water removed = 4 liters. Remaining milk = 12 - 6 = 6 liters Remaining water = 8 - 4 = 4 liters 10 liters of pure milk are added, therefore total milk = (6 + 10) = 16 liters. The ratio of milk and water in the new mixture = 16:4 = 4:1 If the process is repeated one more time and 10 liters of the mixture are removed, then amount of milk removed = 4/5 * 10 = 8 liters. Amount of water removed = 2 liters. Remaining milk = (16 - 8) = 8 liters. Remaining water = (4 -2) = 2 liters. The required ratio of milk and water in the final mixture obtained = (8 + 10):2 = 18:2 = 9:1.

In what ratio should two varieties of sugar of Rs.18 per kg and Rs.24 kg be mixed together to get a mixture whose cost is Rs.20 per kg?

11:03
23:01
31:02
42:01

How many liters of oil at Rs.40 per liter should be mixed with 240 liters of the second variety of oil at Rs.60 per liter so as to get a mixture whose cost is Rs.52 per liter?

1120 liters
2180 liters
3110 liters
4160 liters

Two varieties of wheat - A and B costing Rs. 9 per kg and Rs. 15 per kg were mixed in the ratio 3 : 7. If 5 kg of the mixture is sold at 25% profit, find the profit made?

Let the quantities of A and B mixed be 3x kg and 7x kg. Cost of 3x kg of A = 9(3x) = Rs. 27x Cost of 7x kg of B = 15(7x) = Rs. 105x Cost of 10x kg of the mixture = 27x + 105x = Rs. 132x Cost of 5 kg of the mixture = 132x/10x (5) = Rs. 66 Profit made in selling 5 kg of the mixture = 25/100 (cost of 5 kg of the mixture) = 25/100 * 66 = Rs. 16.50

In a mixture of milk and water, the proportion of milk by weight was 80%. If, in a 180 gm mixture, 36 gms of pure milk is added, what would be the percentage of milk in the mixture formed?

Percentage of milk in the mixture formed = [80/100 (180) + 36] / (180 + 36) * 100% = (144 + 36)/216 * 100% = 5/6 * 100% = 83.33%.

In a can, there is a mixture of milk and water in the ratio 4 : 5. If it is filled with an additional 8 litres of milk the can would be full and ratio of milk and water would become 6 : 5. Find the capacity of the can?

Let the capacity of the can be T litres. Quantity of milk in the mixture before adding milk = 4/9 (T - 8) After adding milk, quantity of milk in the mixture = 6/11 T. 6T/11 - 8 = 4/9(T - 8) 10T = 792 - 352 => T = 44.

In what ratio should a variety of rice costing Rs. 6 per kg be mixed with another variety of rice costing Rs. 8.75 per kg to obtain a mixture costing Rs. 7.50 per kg?

Let us say the ratio of the quantities of cheaper and dearer varieties = x : y By the rule of allegation, x/y = (87.5 - 7.50) / (7.50 - 6) = 5/6

A mixture of 70 litres of milk and water contains 10% water. How many litres of water should be added to the mixture so that the mixture contains 12 1/2% water?

Quantity of milk in the mixture = 90/100 (70) = 63 litres. After adding water, milk would form 87 1/2% of the mixture. Hence, if quantity of mixture after adding x liters of water, (87 1/2) / 100 x = 63 => x = 72 Hence 72 - 70 = 2 litres of water must be added.

10.

All the water in container A which was filled to its brim was poured into two containers B and C. The quantity of water in container B was 62.5% less than the capacity of container A. If 148 liters was now transferred from C to B, then both the containers would have equal quantities of water. What was the initial quantity of water in container A?

B has 62.5% or (5/8) of the water in A. Therefore, let the quantity of water in container A(initially) be 8k. Quantity of water in B = 8k - 5k = 3k. Quantity of water in container C = 8k - 3k = 5k Container: A B C Quantity of water: 8k 3k 5k It is given that if 148 liters was transferred from container C to container B, then both the containers would have equal quantities of water. 5k - 148 = 3k + 148 => 2k = 296 => k = 148 The initial quantity of water in A = 8k = 8 * 148 = 1184 liters.


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