Aptitude - Ratio and Proportion - Discussion

Take it a simple way:

60 litre mixture
2:1 is the ratio means
Mixture is divided into 2+1 = 3 parts i.e, 30lt *3 = 60lt

Given 2:1 = milk: water = 40: 20
Now to make it 1:2
When 40:80=1:2
So, 80-20=60 lt water is added to bring out the ratio.

How can we assume that the second ratio (1:2) given in the problem for next 60 liters ?

Total Mixture 60 liter and ration of the milk and water is 2:1.
Then milk is 40 lit and water is 20 lit.

If you go options 40 has to be correct ?
40 : 20 => 40: 20+60 => 40: 80 => 1:2.

Ramesh Nicely explained .....

The original ratio is 2:1.

That means 40 liters milk and 20 liters water.

We have to add x liters of water so that ratio becomes 1:2.

Here milk quantity doesn't change.

So in 1:2 ratio.

1 part is equal to 40liters.

2 parts-------------------?

80liters.

So the quantity of water to be added is 80-20=60.

@Bagavathi.

In 60lts of mixture the ratio of milk and water is 2:1. It means 40lts of milk and 20 lts of water. In the question he just asked only how much of water is added to make the ratio of milk dan water to 1:2.

So the quantity of milk is unchanged i.e, 40lts. and the quantity of water required is 60lts. Now the total quantity of mixture is 120 lts in which 40lts of milk is 1part. In the old ratio the total mixture is 60lts so 40 lts of milk is 2part.

Thank you karthik negi for your clear and crisp explanation.

With the help of first ratio 2:1 we find already milk 40 liters and 20 liters water (total 60 liter of mixture). But I don't why we taken 40 liters of milk is consider as 1 part for the new ratio (1:2). Actually in old ratio 40 liter is 2 part. Please any one clarify please.

Good Kartik Negi your ans is right and simple..

Let the ratio be 2x and 1x
add it to get,
2x+1x=60
3x=60
x=20
now,milk=2x20=40ltr.
and water=1x20=20ltr.
we know that something is added to water..
therefore,new ratio is 1:2 after adding the quantity of water
therefore,40/20+x=1/2 ( note that x=new quantity of water that is to be added)
cross multiply it and u will get the ans. =60
Hence proved.