Five litres of water is added to a certain quantity of pure milk costing ₹60 per litre. If by selling the mixture at the same price (₹60 per litre), a profit of 20% was made, then the amount of pure milk in the mixture is:
Answer & explanation
Correct answer: option 4
Let the amount of pure milk be x litres
then cost of milk = 60 x
After adding 5 liters of water = x + 5 litres
Selling price of mixture @ 60(x+5) = 60x + 300
gain = 300, gain % = 20
$C.P=(\frac{100}{100+gain %}).S.P$
$⇒60x=(\frac{100}{100+20}).(60x+300)$
$⇒60x=\frac{100}{120}×(60x+300)$
⇒ 60x + 300 = 72x
⇒ 12x = 300
⇒ x = $\frac{300}{12}$ = 25 litres