Question

Find the number of coins 1.5 cm in diameter and 0.2cm thick to be melted to form a right circular cylinder of height 16cm and diameter 6cm

Answer 1

volume of cone ⅓pir²h
=⅓×22/7×3×3×16
=150.85
volume of coin , coin in the shape of cylinder so, pi r²h
= 22/7×0.1×0.1×1.5
=0.047
150.85/0.047
=3209

Answer 2

Hola mate

Here is your answer -

As the coins are in the form of thin cylinder

Volume of each coin = π×(0.75)²×0.2 =0.1125π cm³

Volume of melted cylinder = π× (2.25)²× 10 = 50.625π cm³

number of coin required = (volume of melted cylinder)/(volume of each coin)

= 50.625π/0.1125π = 450 coins