Aptitude - Alligation or Mixture - Discussion

Discussion Forum : Alligation or Mixture - General Questions (Q.No. 9)
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:
1
3
2
3
2
5
3
5
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

Discussion:
63 comments Page 1 of 7.

Cosul said:   7 years ago
X litres to start with so it contains in the below ratio of alcohol and water(assume).

40*x/100 - alcohol and 60*x/100 water,
Now, y litres of whisky to be taken away and added by 19% of y litres of whisky,

So we know when anything is taken away in the mixture, it takes out equal amounts out from the mixture.

hence since y litres is taken out it takes out alcohol in equal ratio i.e(40*y/100), we get the below equation for remaining alchol in the mixture.

(40*x/100 )- (40 *y/100),
Now they say 19% of y litres of alcohol is added so, equations become,
(40*x/100 )- (40 *y/100 ) + 19*y/100 = 26*x/100.

Solving we get 2/3.

Deepak Kumar said:   10 years ago
Its too simple,

According to allegation rule,

Chip/Deep = (Deep-Common)/(Common-Chip).

Chip/Deep = (0.40-0.26)/(0.26-0.19).

Chip/Deep = 0.14/0.07.

Chip/Deep = 2/1.

So, Chip (whisky with 19% alcohol) = 2/3rd of total final mixture.

Deep (whisky with 40% alcohol) = 1/3rd of total final mixture.

Now here is the logic. According to question, whisky containing 40% alcohol (deep) was replaced with whisky containing 19% alcohol (chip) to make this final mixture. So 2/3rd of whisky (40%) was replaced with 2/3rd of whisky (19%).

So answer = 2/3.
(1)

Tejesh said:   9 years ago
1/3 is the wrong answer.

As per Prakash' method, 2/3* 100 is right but it is the amount of alcohol and 1-2/3=1/3 is the answer of whisky which has 19% alcohol. In a question, they told that whisky which has 40% alcohol replaced by whisky of 19 % alcohol so its prove that 1/3 is the answer of whisky which has 19% & 40% combined alcohol. But in a problem, they asked replaced whisky means whisky which has 40% alcohol. So please tell anyone in detail what is the answer still I am not getting the answer.

Anupam said:   5 years ago
Let, the total original amount of whiskey = 10 ml, i.e. 4 ml alcohol and 6 ml non-alcohol.

Let x ml be the amount removed,
Total alcohol left = 4-0.4x.

New quantity of whiskey added = x ml out of which 0.19 is the alcohol.

Thus, the final quantity of alcohol,
= 4-0.4x+0.19x=4-0.21x.
ATQ, (4-0.21x)= 26% of 10 [Here, initially 10],
=> x = 20/3 ml.

As per the question, we need to find the x ml removed as a ratio of the initial volume,
= (20/3)/10 = 2/3 (Answer).

Rohan said:   5 years ago
By using alligation method we can easily get the ratio in which they were mixed together.

So,
= (26-19) : (40-26),
= 7:14,
= 1:2.
So 1/3 of first and 2/3 of second are mixed to make the third mixture in which 26% alcohol is there;

Now the question is asking for the quantity which is removed or taken out from the first jar
If 1/3 of jar A is used to make a new mixture.
So, 2/3 of jar A is taken out or replaced.
(17)

Prakash said:   1 decade ago
Suppose the vessel initially contains 100 litres of liquid.
So, it contain 40 lit alchohal, 60 lit water.
Let x litres of this liquid be replaced .

Quantity of alchohal in new mixture =(40-40x/100+19x/100)
=40-21x/100
Now vessel contain 26% alcohol

So, 40-21x/100=26
x=2/3*100.

Atchiya said:   1 decade ago
According to mixture allegation rule.. we have place the chaeper one on left side and the dearer one on right side... why here that rule is not followed

acoording to that 14:7 comes..so lastly 2:1 is the ratio and
and the first jar is compared s 2/3 parts (i.e)2:3 .. is this correct ?? plz answer this !!!

Ramakrishna said:   10 years ago
I think this is the easy method.

If the 40% will alcohol is a1 = 40% and another 19% is a2 = 19%.

And in the resultant is A = 26%.

Any solution Alligation is given as:

Average A = (n1a1*n2a2)/(n1+n2).

n1:n2 = (a1-A)/(A-a2).

n1:n2 = (40-26):(26-19) then the result is 14:7 that will give 2:1.

Rabindra said:   3 years ago
Here, 1:2 is not mixture ratio.it's ratio between 1st mixture quantity after removal and 2nd added mixture quantity.

Here a word used same amount of mixture "replaced".

Mixture amount ratio = 1:2 means total mixture amount =3 part.

Added mixture amount = 2/3. Which was replaced.
(7)

Dileep Nampoothiri said:   5 years ago
Consider 100L of Whiskey Mixture.
40L alcohol and 60L Water.

Let x be the amount of whiskey replaced in Litres. So 0.4x is the alcohol removed and 0.19x is the alcohol added. 26L is the new alcohol content.
We will do an alcohol balance.
40-0.4x+0.19x = 26 -----> x = 200/3.
x/100 = 2/3.
(6)


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