The quantity of water that must be added to 36 litres of pure milk at $1\frac{1}{2}$ litres for ₹75 so as to have mixture worth ₹40 a litre is :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 9 litres
Cost per litre = $75×\frac{2}{3} = 50$ per litre
Total cost = $36×50=1800$
Let the quantity of the water be x litre.
Total volume = $(36+x)L$
$⇒\frac{1800}{36+x}=40$
$⇒1800=40(36+x)$
$⇒36+x=45$
$⇒x=9$ litres