Mixture and Alligation (Railway Maths) (Part – I)

Total Questions: 50

1. X and Y are two alloys of Gold and Platinum prepared by mixing the metals in the ratio of 5 : 2 and 5 : 7, respectively. If we melt equal quantities of the alloys to form a third alloy Z, then the ratio of the quantity of Gold to the quantity of Platinum in Z will be: [Group D 17/08/2022 (Morning) ]

Correct Answer: (c) 95 : 73
Solution:

2. In what ratio should sugar costing ₹45 per kg be mixed with sugar costing ₹52 per kg so that by selling the mixture at ₹55.20 per kg, there is a profit of 15%? [Group D 01/09/2022 (Afternoon) ]

Correct Answer: (a) 4 : 3
Solution:

3. Two mixtures A and B have the following compositions. Mixture A has copper and tin in the ratio 1 : 2. Mixture B has copper and tin in the ratio 1 : 3. If equal quantities of mixtures A and B are used for producing mixture C, then find the ratio of copper and tin in mixture C. [Group D 28/09/2022 (Afternoon) ]

Correct Answer: (a) 7 : 17
Solution:

4. In a mixture of 90 litres, the ratio of milk to water is 4 : 1. In another mixture of 90 litres, the ratio of milk to water is 3 : 2. What is the positive difference between the quantities of milk in the two mixtures ? [NTPC CBT II Level 5 (12/06/2022) Shift 1 ]

Correct Answer: (b) 18 litres
Solution:

5. In a mixture of liquid, 1/5 part is acid, 3/5 part is alcohol and the remaining part is water. If the total quantity of the mixture is 20 litres, then how much water (in litres) does the mixture contain? [NTPC CBT - I 29/12/2020 (Evening) ]

Correct Answer: (c) 4
Solution:

6. If two liters of water is evaporated from a 5 liter solution containing 3% salt, then what is the percentage of salt in the remaining solution? [NTPC CBT - I 04/03/2021 (Morning) ]

Correct Answer: (a) 5%
Solution:

7. A trader mixes 20kg of one variety of rice at Rs52 per kg with 60kg of another variety at Rs36 per kg. If he sells that mixed rice at Rs44 per kg, his profit percent is ______. [NTPC CBT - I 01/04/2021 (Evening) ]

Correct Answer: (a) 10
Solution:

8. In a test paper, correct answers fetch three marks and there is a penalty of one mark for each wrong answer. A student who attempts 76 questions gets 144 marks. How many questions did the student get right? [NTPC CBT - I 24/07/2021 (Morning) ]

Correct Answer: (d) 55
Solution:

9. From a container of 50 litres pure milk, 10 litres milk is taken out and replaced by 10 litres of water. If this process is repeated thrice, what is the ratio of water to milk finally? [RRB JE 27/05/2019 (Evening) ]

Correct Answer: (c) 61 : 64
Solution:

10. The ratio of milk to water in 10 liters of a mixture is 3 : 2. If this ratio is to be made 2 : 3, then the quantity of water to be added to the mixture is: [Group D 29/08/2022 (Morning) ]

Correct Answer: (c) 5 liters
Solution: