A milk vendor has 21 litres of cow milk, 42 litres of toned milk and 63 litres of double toned milk. If he wants to pack them in cans, so that each can contains same litres of milk and does not want to mix any two kinds of milk in a can, then the least number of cans required is = ?

Explanation:-

For least or minimum number of cans we should have maximum capacity cans for required quantity
⇒ For this we take HCF of given quantities.
HCF (21, 42, 63) = 21
∴ Maximum capacity of a can = 21 litres
∴ Number of cans of cow milk
$${\text{ = }}\frac{{21}}{{21}}{\text{ = 1}}$$ ∴ Number of cans of toned milk $${\text{ = }}\frac{{42}}{{21}} = 2$$ ∴ Number of cans of double toned milk $${\text{ = }}\frac{{63}}{{21}} = 3$$ ∴ Total number of cans = 1 + 2 + 3 = 6