How many silver coins, 1.75 cm in diameter and of thickness 2 mm, must be melted to forma cuboid of dimensions 5.5 cm × 10 cm × 3.5 cm?
Coins are cylindrical in shape.
Height (h1) of cylindrical coins = 2 mm = 0.2 cm
Radius (r) of circular end of coins =
= 0.875 cm
Let n coins be melted to form the required cuboids
Volume of n coins = Volume of cuboids
n * π * r2 * h1 = l * b * h
n * π * (0.875)2 * 0.2 = 5.5 * 10 * 3.5
n = 
= 400
Hence,
The number of coins melted to form the given cuboid is 400
6