Aptitude - Alligation or Mixture
Exercise : Alligation or Mixture - General Questions
- Alligation or Mixture - Formulas
- Alligation or Mixture - General Questions
6.
A dishonest milkman professes to sell his milk at cost price but he mixes it with water and thereby gains 25%. The percentage of water in the mixture is:
4%
6
%
%20%
25%
Answer: Option
Explanation:
Let C.P. of 1 litre milk be Re. 1
Then, S.P. of 1 litre of mixture = Re. 1, Gain = 25%.
| C.P. of 1 litre mixture = Re. |  |
100 | x 1 |  |
= | 4 |
| 125 | 5 |
By the rule of alligation, we have:
| C.P. of 1 litre of milk C.P. of 1 litre of water | |||||
| Re. 1 | Mean Price
| 0 | |||
|
|
||||
 Ratio of milk to water = |
4 | : | 1 | = 4 : 1. |
| 5 | 5 |
| Hence, percentage of water in the mixture = | |
1 | x 100 | % |
= 20%. |
| 5 |
7.
How many kilogram of sugar costing Rs. 9 per kg must be mixed with 27 kg of sugar costing Rs. 7 per kg so that there may be a gain of 10% by selling the mixture at Rs. 9.24 per kg?
Answer: Option
Explanation:
S.P. of 1 kg of mixture = Rs. 9.24, Gain 10%.
| C.P. of 1 kg of mixture = Rs. |
|
100 | x 9.24 | |
= Rs. 8.40 |
| 110 |
By the rule of allilation, we have:
| C.P. of 1 kg sugar of 1st kind Cost of 1 kg sugar of 2nd kind | ||
| Rs. 9 | Mean Price Rs. 8.40 | Rs. 7 |
| 1.40 | 0.60 | |
Ratio of quantities of 1st and 2nd kind = 14 : 6 = 7 : 3.
Let x kg of sugar of 1st be mixed with 27 kg of 2nd kind.
Then, 7 : 3 = x : 27
 x = |
|
7 x 27 | |
= 63 kg. |
| 3 |
8.
A container contains 40 litres of milk. From this container 4 litres of milk was taken out and replaced by water. This process was repeated further two times. How much milk is now contained by the container?
Answer: Option
Explanation:
| Amount of milk left after 3 operations = |  |
40 | |
1 - | 4 | |
3 |  litres |
| 40 |
| = | |
40 x | 9 | x | 9 | x | 9 | |
= 29.16 litres. |
| 10 | 10 | 10 |
9.
A jar full of whisky contains 40% alcohol. A part of this whisky is replaced by another containing 19% alcohol and now the percentage of alcohol was found to be 26%. The quantity of whisky replaced is:
Answer: Option
Explanation:
By the rule of alligation, we have:
| Strength of first jar Strength of 2nd jar | ||
| 40% | Mean Strength 26% | 19% |
| 7 | 14 | |
So, ratio of 1st and 2nd quantities = 7 : 14 = 1 : 2
| Required quantity replaced = |
2 |
| 3 |
10.
In what ratio must water be mixed with milk to gain 16
% on selling the mixture at cost price?
% on selling the mixture at cost price?
Answer: Option
Explanation:
Let C.P. of 1 litre milk be Re. 1.
| S.P. of 1 litre of mixture = Re.1, Gain = | 50 | %. |
| 3 |
| C.P. of 1 litre of mixture = |
|
100 x | 3 | x 1 | |
= | 6 |
| 350 | 7 |
By the rule of alligation, we have:
| C.P. of 1 litre of water C.P. of 1 litre of milk | |||||
| 0 | Mean Price
| Re. 1 | |||
|
|
||||
| Ratio of water and milk = |
1 | : | 6 | = 1 : 6. |
| 7 | 7 |
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