Aptitude - Alligation or Mixture - Discussion
Discussion Forum : Alligation or Mixture - General Questions (Q.No. 1)
1.
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?
Answer: Option
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 | + x |  |
litres |
| 8 |
| Quantity of syrup in new mixture = | |
5 - | 5x | |
litres |
| 8 |
 |
|
3 - | 3x | + x | |
= | |
5 - | 5x | |
| 8 | 8 |
5x + 24 = 40 - 5x
10x = 16
| x = |
8 | . |
| 5 |
| So, part of the mixture replaced = | |
8 | x | 1 | |
= | 1 | . |
| 5 | 8 | 5 |
Discussion:
201 comments Page 21 of 21.
Ankush said:
3 weeks ago
3Lwater + 5L syrup = 8L mix.
Now 1 unit of mix will also have 3 parts water and 5 parts syrup,
Let 1 unit be 800 ml for easy calculation.
And in 800ml we have 300ml water + 500ml syrup
Now, remove 1 unit from the total, you will have a mix of 7.2L.
removed 1unit = 800ml in 7.2L × 5/8 = 4.5 L syrup left.
And add 800ml of water in its place.
New ratio of mix 4.5l syrup: 2.7 old +0.8 newly added
4.5:3.5 we need 4:4 for both equal
Remove 1 more unit from the mix.
7.2 - 0.8 = 6.4L.
Syrup left 6.4L × 5/8 = 4.0L
Add water in place of 800ml
Now you have 4L syrup: 4L water.
Replacement of syrup with water = 800ml × 2 = 1.6L.
Now, how much replacement from the original 8L in ratio?
So, 1.6/8 total replacement reduces to 1/5(ans).
Now 1 unit of mix will also have 3 parts water and 5 parts syrup,
Let 1 unit be 800 ml for easy calculation.
And in 800ml we have 300ml water + 500ml syrup
Now, remove 1 unit from the total, you will have a mix of 7.2L.
removed 1unit = 800ml in 7.2L × 5/8 = 4.5 L syrup left.
And add 800ml of water in its place.
New ratio of mix 4.5l syrup: 2.7 old +0.8 newly added
4.5:3.5 we need 4:4 for both equal
Remove 1 more unit from the mix.
7.2 - 0.8 = 6.4L.
Syrup left 6.4L × 5/8 = 4.0L
Add water in place of 800ml
Now you have 4L syrup: 4L water.
Replacement of syrup with water = 800ml × 2 = 1.6L.
Now, how much replacement from the original 8L in ratio?
So, 1.6/8 total replacement reduces to 1/5(ans).
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