Aptitude - Alligation or Mixture - Discussion

Discussion Forum : Alligation or Mixture - General Questions (Q.No. 4)
4.
A milk vendor has 2 cans of milk. The first contains 25% water and the rest milk. The second contains 50% water. How much milk should he mix from each of the containers so as to get 12 litres of milk such that the ratio of water to milk is 3 : 5?
4 litres, 8 litres
6 litres, 6 litres
5 litres, 7 litres
7 litres, 5 litres
Answer: Option
Explanation:

Let the cost of 1 litre milk be Re. 1

Milk in 1 litre mix. in 1st can = 3 litre, C.P. of 1 litre mix. in 1st can Re. 3
4 4

Milk in 1 litre mix. in 2nd can = 1 litre, C.P. of 1 litre mix. in 2nd can Re. 1
2 2

Milk in 1 litre of final mix. = 5 litre, Mean price = Re. 5
8 8

By the rule of alligation, we have:

C.P. of 1 litre mixture in 1st can    C.P. of 1 litre mixture in 2nd can
3
4
Mean Price
5
8
1
2
1
8
1
8

Ratio of two mixtures = 1 : 1 = 1 : 1.
8 8

So, quantity of mixture taken from each can = 1 x 12 = 6 litres.
2

Discussion:
74 comments Page 3 of 8.

Dinesh said:   6 years ago
How will you find the quantity of mixture?

Prakhar said:   6 years ago
Best explanation, thanks @Ajay.

Amin said:   6 years ago
Why we take 12 litres of milk as x+y=12?

Amit Ambadkar said:   6 years ago
Let's see 2 methods to solve the problem.
Let 1st can contain x lit of mixture(means 0.25x lit water and 0.75x lit milk).
2nd can contain y lit of mixture(means 0.5y lit milk and 0.5y lit water).
After mixing both the ratio of water to milk is 3:5.
So,
(0.25x+0.5y):(0.75x+0.5y) = 3:5.
After solving x:y=1:1,
And we have x+y=12,
So x=y=6.

Guru Prasad said:   6 years ago
Alternate method:
-
CAN:1---> 25% water and the remaining 75% milk.
CAN:2---> 50% water and 50% milk.

Given ratio is 3:5. since only the quantity of milk is to be estimated therefore there is 5/8 of milk present in the mixture. converting this into percentage it is 62.50%.

By using allegation:-
{75% = M & 50% = N and D = 62.50%}--------> General Assumption.

M - D = 75% - 62.50%
= 12.50%.

D - N = 62.50% - 50%,
= 12.50%.

(M - D) : (D - N) = 1 : 1.

Therefore the quantity of milk to be mixed from each of the containers in order to 12 litres of milk is;

(1/2) * 12
= 6 litres. since the obtained ratio is 1:1 therefore from container-1 it is 6 litres and from container-2 it is also 6 litres.
(2)

Nani said:   7 years ago
Nice explanation, thanks a lot @Vivek Kumar.

Sravani said:   7 years ago
So in this problem,

5/8 is taken as the total mixture is in the ratio 3:5(water:milk).
so as we are calculating for milk quantity in the aligation process, the milk quantity is according to ratio 5/3+5=5/8.

Hope you understand this.

Sridharsan said:   8 years ago
Actually, we need 12 ltrs of milk, here where is 12 ltr of milk, 6+6=12 (it is a mix, not purely milk).


Please explain in detail.

Kabir said:   8 years ago
12 liter milk or mix. I am confused. Is this question in right mood. Please anyone explain the question.

Odett said:   8 years ago
Very good explanation @Moncy.


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