Question

a milkman has one bucket of milk of 80% purity and he has another bucket of milk of 60% purity how much milk of each kind should mix to supply 20 litre of milk of 75% purity​

Answer 1

Answer:

Step-by-step explanation: To get 20l milk , let us assume that we use a litres of 1st bucket(80%) and b litres of 2nd bucket(60%)

Bucket 1: One litres contains 80% milk, 80%  of 1 litre = 0.8 litres

The rest will be impurity:

1 litre - 0.8 litres= 0.2 litres

         So, a litres of bucket 1 milk will contain 0.8*a litres of pure milk and 0.2*a litres impurities

Similarly for bucket 2 , 60% is pure milk, therefore

One litres contains 60%  of 1 litre = 0.6 litres of pure milk

The rest will be impurity:

1 litre - 0.6 litres= 0.4 litres

So, b litres of bucket 1 milk will contain 0.6*b litres of pure milk and 0.4*b litres impurities

If 20 litres of milk with 75% purity is to be made , amount of pure milk will be 75% × 20 = 15 litres pure milk and (20-15) litres, i.e. 5 litres

There fore , when we mix the milk, from both buckets:-

Pure milk:

0.8a + 0.6b = 15---- 1

Impurity:

0.2a + 0.4b = 5

Multiplying 4 at both sides we get.,

0.8a + 1.6b = 20-----2

Subtracting ----1 from ----2, we get

 0.8a + 1.6b = 20

- 0.8a + 0.6b = 15

       1.0 b = 5

So, b = 5

Using this in ------1 we get,

0.8a + 0.6(5) = 15

0.8a + 3 = 15

0.8a = 15-3 = 12

a = 12÷0.8 = 15

Therefore , we must add 15 litres from the 1st bucket and 5 litres from the second...

Hope this helps.. :)

Answer 2

Answer:

Step-by-step explanation: