Aptitude - Alligation or Mixture - Discussion

Discussion Forum : Alligation or Mixture - General Questions (Q.No. 6)
6.
A dishonest milkman professes to sell his milk at cost price but he mixes it with water and thereby gains 25%. The percentage of water in the mixture is:
4%
6%
20%
25%
Answer: Option
Explanation:

Let C.P. of 1 litre milk be Re. 1

Then, S.P. of 1 litre of mixture = Re. 1, Gain = 25%.

C.P. of 1 litre mixture = Re. 100 x 1 = 4
125 5

By the rule of alligation, we have:

C.P. of 1 litre of milk C.P. of 1 litre of water
Re. 1 Mean Price
Re. 4
5
0
4
5
1
5

Ratio of milk to water = 4 : 1 = 4 : 1.
5 5

Hence, percentage of water in the mixture = 1 x 100 % = 20%.
5

Discussion:
65 comments Page 2 of 7.

Vikatakavee said:   1 decade ago
Let us consider C.P of the milk = Rs. 100 (milk is 100%).

--> S.P also = 100.

If you are getting 25% profit S.P = 1.25 C.P.
--> 100 = 1.25 C.P.
--> C.P = 80.

C.P 80 means 80% of milk. So remaining 20% water.

Vishal said:   1 decade ago
Let the price of the milk is 100% and he is getting the profit of 25% so the selling price must be 125%.

Now according the formula:

[(x/x+100)*100]%

{if price is 25% more than original then the milk is [25/100+25*100]% less than}

So,
[25/125*100]% = 20%.
He is selling the milk mixed with 20% of water.

Anamika said:   1 decade ago
Where it is given that C.P. is rupee one?

Would you please explain.

Ted said:   1 decade ago
You are assuming CP. AS rupee one for easy calculation. Thats all!

Prabhat Ranjan said:   1 decade ago
I have very simple solution for the above problem, which is as follow:

Suppose we have 100 kg of milk @ Rs.1 per kg Cost price.
Total cost price = Rs.100.

Profit is given 25%, therefore SP of 100kg milk = Rs. 125.

But according to question, he sells at CP. therefore he has to mix 25 litres of water.
Therefore % of water in mixture = 25*100/125 = 20%.

DHANANJAY SINGH said:   1 decade ago
CP = 100 RS FOR 100 LITERS.

BUT ACTUALLY IT HAS 125 LITERS (25 LITERS WATER).

SO CP OF 100 LITERS BE RS 100.

CP OF 125 LITERS BE RS 125.

PROFIT = 125-100/125*100=20%.

Thamaraikannan said:   1 decade ago
100:gain%.

So 100:25 (this meant for 100% we get 25% profit).

Now 4:1 (for every 4l milk 1l water to be added).

Ratio wise 1l. Then percentage wise (1/5)*100 = 20%.

Vishnu said:   10 years ago
For example he sells 1 liter of mixture =0.8 liter milk 0.2 liter water.

I liter is equal to 125% (100% cp + profit 25 %).

Thus cost price achieved by selling 0.8 liters of milk.

Profit by 0.2 liters which is 25 %.

125% = 0.2/0.8*100.

Sreyansh joshi said:   10 years ago
I am still not getting this according to alligation rule the cheaper material should be used and in this solution they have considered milk as the cheaper material.

Parvy Govil said:   10 years ago
Let the original amount of milk be 100 and the cost price is Rs. 1/L.

CP1 = 100.
SP1 = 100.

Case 2 : When the milk is milk with x liters of water milk remaining is 100-x.

But now the SP is 100.

Given gain% = 25.

Thus, (100-(100-x))/100-x *100 = 25.

x = 20 liters.

Therefore, 20 L of water is added to 80 liters of milk so that the quantities remain the same however the selling price now makes all the difference!


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