Question

Roshan Lal is a milk man and supplies
milk from door to door in his village Kotli.
Normally his 20 litres of a mixture
contains milk and water in the ratio
3: 1. He has a habit of mixing water to
milk. So how much milk must he add to
this mixture to get a mixture containing
milk and water in the ratio 4:1?​

Answer 1

Answer:

5l

Step-by-step explanation:

In a mixture of 20l of milk and water the quantity of milk = 20 × 3/4 l = 15l

And the quantity of water = 20 × 1/4 = 5litres

Now let he add x litres of milk.

According to question,

15 + x : 5 = 4: 1

15+x/5 = 4/1

1(15+x) = 4×5

15 +x = 20

x = 20 - 15 = 5 litres.

Alternative method:

In a mixture of 20l of milk and water the quantity of milk = 20 × 3/4 l = 15l

And the quantity of water = 20 × 1/4 = 5litres

Quantity of water in the new mixture = :1 = 5 l

Quantity of milk in the new mixture = :4= 5/1 × 4 =20 l

So he added = 20l - 15l = 5l