Question

How many coins 1.75 cm in diameter and 2 mm thick must be melted to form a cuboid of dimensions and m into 10 cm and 27 cm?

Answer 1

Diameter of the coin = 1.75 cm Radius, r =  

Height = 2 mm = 0.2 cm

Volume of 1 coin = r2h = 0.2 cm3

Volume of cuboid = 11 10 7 cm3

Since, the coins are melted to form a cuboid, so the total volumes of all coins will be equal to the volume of the cuboid.

Let the number of coins be n.

So, volume of n coins = volume of cuboid

n = = 1600