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 5 of 8.

Dhanwin said:   1 decade ago
Different approach:
==============

Can 1 ---- 25% water + 75% milk.
Ratio ---- 1:3 (25/75 = 1/3).

Can 2 ---- 50% water + 50% milk.
Ratio ----- 1:1 (50/50 = 1/1).

If I take p liters from can 1 and q liters from can 2.

So that total should be 12 liters with water : milk = 3 : 5.

So I get following equation.

P+q/3p+q = 3/5 -------- (equation 1).

Now try checking the given options in questions and the answer should be the "option" which satisfies the (equation 1).

Ex:

Let p = 6 and q = 6.

Then 6+6/(3*6+6) = 3/5.

So the equation 1 is satisfied. So the answer is 6 liters from can 1 and 6 liters from can 2.

Other options given won't satisfy the (equation 1).

Sri said:   1 decade ago
Can anybody tell me how 5/8 arrived here?

Sri Divya said:   1 decade ago
Hi friends, Please explain how 5/8 became the mean price?

How to calculate mean price?

Gokulpriya said:   1 decade ago
How did 5/8 become mean prize what is this value?

Vaishnavi said:   1 decade ago
Please explain me in a simple way guys?

I can't get the logic?

ANAND PATEL said:   1 decade ago
From the first can mixture is X liter.

From the first can mixture is Y liter.

NOW X + Y = 12.

IN 12 LITER portion of water is 4.5 and milk IS 7.5 LITER.

X( (1/4)+ (1/2))+ Y ((3/4)+(1/2))= 4.5 + 7.5.

SO X( (1/4)+ (1/2))= 4.5 => X= 6 LITER.

Y ((3/4)+(1/2)) = 7.5 +> Y = 6 LITER.

Meeran said:   1 decade ago
Water : Milk
Can 1 1 : 3
Can 2 1 : 1

Required ratio = 3 : 4.

Therefore ratio of can1+ can2+ added quantity = required quantity.

1+1+1 : 3+1+1 is the only possible way, ratio added must b,
1 : 1.

Hence, option B, 6 : 6 is only possible which can give 1 : 1 ratio.

Vikram Ojha said:   1 decade ago
1st can Water:milk = 1:3.
In 2nd can water:milk = 1:1.

In 12 liters = water:milk = 3:5.

So in 12 liters we have 3(12)/8 = 4.5 liter of water.

Lets us consider we have x liters of water in new mix.

So our equation will be,
1(x)/4 + 1(x)/2 = 4.5.
x = 6 liters.

So amount of water in new mixture = 6 liters.
And that of milk will be = 12-x = 6 liters.

Dhruv Sahni said:   1 decade ago
Container A has 25% water, Container B has 50% of water and after mixing these two final mixture has 3/8 -> 37.5% of water.

So by allegation method the ratio of A and B in final mixture will be 25% 50% 37.5%.

50%-37.5% : 37.5%-25%.

= 12.5% = 12.5% = 1:1.

So Ratio of A:B in final mixture is 1:1, hence in 12 liter of mixture there will be 6L of A and 6L of B.

Ajinx999 said:   1 decade ago
Let x L of milk be removed from can A (25% water). Since, 12 L of milk is finally required, (12-x) L of milk is removed from can B (50% water).
Considering following ratio

(water from A) + (water from B) 3
--------------------------------------- = ---
(pure_milk from A) + (pure_milk from B) 5

(1/4)x + (1/2)(12-x) 3
-------------------- = ---
(3/4)x + (1/2)(12-x) 5

Solving for x, x = 6
So 6 L is removed from can A and (12-6) = 6 L is removed from can B.


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