Question

A milkman mixes 20 liters of water with 80 liters milk.After selling one-fourth of the mixture,he adds water to replenish the quantity that he has sold.What is the current proportion of water to milk?

Answer 1

Ratio of water to milk = 20/80 = 1:4

(1/4) x 100 = 25 litres.

Part sold (water) = (1/5) x 25 = 5 litres

Part sold (milk) = 20 litres

He now adds 25 litres of water to replenish the quantity.

Now, out of 100 litres of the mixture there is (15+25) litres of water = 40 litres of water.

Hence, milk is 60 litres.

water : milk = 40/60 = 2:3

Answer 2

Concept

A ratio is defined as a comparison of two quantities of equal units and indicates how much of one quantity is contained in the other quantity.

Given

We have given the ratio of water to the milk as 20:80.After selling one-fourth of the mixture, he adds water to replenish the quantity that he has sold

Find

We are asked to determine the current proportion of water to milk.

Solution

The original mixture consisted of 100 liters of liquid, 80 liters of which  was milk and 20 liters of water. It's 80% milk and 20% water.

The ratio of water to milk  is 20:80

Mixture just taken  $= \frac{1}{4}\times100 = 25 liters$

Water content of these 25 liters $= \frac{20}{100}\times 25 = 5 liters$

Percentage of these 25 liters of milk $= \frac{80}{100}\times 25 = 20 liters$

Milkman replaces 25 liters with all water

Currently, 15 liters of water and 60 liters of milk remain in the mixture

Therefore, the amount of water in the new mixture $= 20-5 + 25 = 40 liters$

Amount of milk in the new mixture $= 80-20 = 60 liters$

The  water to milk ratio is $40:60\ or\ 2: 3$

Therefore, the curent proportion of water to milk is 2:3.

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