Question

A milkman has 80% milk in stock of 800 litres of adulterated milk. How much 100% pure milk is to be added to it so that purity is between 90% AND 95%. How much milk he should add to his stock to obtain 99% pure milk?

Answer 1

to keep the milk between 90%-95% we must add the 100%milk greater than or equal to 800 liters and less than or equal to 2400 liters
to make the milk 99% pure we must add 72800 liters of milk