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?
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1
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1
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1
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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 10 of 21.

Guru said:   1 decade ago
I think the issue with some of the guys here is they find these mathematical theories hard to understand. Let me make it simpler for them.

They didn't give the volume of vessel in the question so never mind that. The vessel contains 8 parts of liquids (i.e. - 3 parts of water and 5 parts of syrup).

What they are asking is to make the mixture into half water and half syrup i.e. - 4 parts of water and 4 parts of syrup. To make it happen you need to take 1 part of syrup out of the vessel (which is 1/5th of the total syrup) and add 1 part of water instead and thus you get the answer 1/5!

Rahul Wiley said:   1 decade ago
Hey Keep it simple.

Fraction of syrup in final Mixture = (Fraction of syrup in initial mixture)*(1 - x/v).

Where,
x is the Quantity of mixture removed.
V is the volume of the Mixture.

Rajesh said:   1 decade ago
Simple friends,

Here totally 8 parts (5 part syrup + 3 part water).

To make it equal (4 parts syrup + 4 part water).

So, we have to draw 1 part from syrup (i.e.,) 1/5.

Usha said:   1 decade ago
How we get 5x+24=40-5x?

K.S PAL said:   1 decade ago
A container is filed with 3 part water & 5 parts syrup, so total we have 8 parts or mathematically we can say,

3/8 water.
5/8 syrup.

Suppose we withdraw x parts of mixture then this will contain,

3/8(x) water.
5/8(x) syrup.

Now we have to add same amount of water the amount of water and syrup will be equal, so mathematically.

3/8-3/8(x) +x = 5/8-5/8(x).

It will give x = 1/5.

Jerry said:   1 decade ago
Why do we add y in this step 3/8[x-y] + y = 5/8[x-y] ?

The rest of the steps are perfectly understood! Thanks :),.

Mohan said:   1 decade ago
Hey guys I think this is useful formula for this question:

1/2(difference in parts/greater part).

1/2(5-3/5).

1/5.

Anonymous said:   1 decade ago
From where did you get 1/8 in finding the final result?

Yogita said:   1 decade ago
How we find the % of thing?

Vaishali Sharma said:   1 decade ago
There has to be a direct formula for this.

Anyone has it?


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