Question

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

Answer 1

Answer: The number of coins required is 1280

Step-by-step explanation:

Number of coins × volume of each coin = Total volume of final cylinder

Let number coins be x

volume of coin/cylinder is calculated using:

$volume of cylinder = \pi r^{2} h$

where r is radius and h is height/thickness of the cylinder/coin

given coin diameter = 1.5 cm, therefore radius = 0.75 cm

given cylinder diameter = 6 cm, therefore radius = 3 cm

Using the equation:

Number of coins × volume of each coin = Total volume of final cylinder

$x (\pi (0.75)^{2} (0.2)) = \pi (3)^ {2} (16)\\\\x = \frac{144}{0.1125}\\\\x = 1280$