Question

How many silver coins 1.75 diameter and of thickness 2mm must be melted to from a cuboid of dimension 5.5cm × 10cm × 3.5cm
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Answer 1

Answer:

400 coins

Step-by-step explanation:

the coin is in the form of cylinder

diameter of cylinder is 1.75 cm

radius = 1.75/2 = 0.875 cm

thickness of coin is 2 mm or 0.2cm

the volume of one coin is πr^2h

$= \frac{22}{7} \times 0.875 \times 0.875 \times 0.2 \\ = 22 \times 0.125 \times 0.875 \times 0.2 \\ = 0.481 {cm}^{3}$

volume of cuboid l × b × h

= 5.5 × 10 × 3.5

= 55 × 3.5

= 192.5

number of coins required to form a cuboid of volume = 192.5 cm^3

$x \times 0.481 = 192.5 \\ x = \frac{192.5}{0.481} \\ x = 400$

we require 400 coins to form a cuboid

hope you get your answer

Answer 2

We have,

Radius of coin = 1.75/2 = 00.875 cm

Thickness, i.e, height = 2/10 = 0.2 cm

The shape of the coin will be like the shape of cylinder

Volume of the coin = πr²h

Volume of the coin = 22/7 × 0.875 × 0.875 × 0.2

Now, Volume of the cuboid = 5.5 × 10 × 3.5

Therefore, Number of coins required to form a cuboid = Volume of the cuboid/Volume of the coin

Number of coins required to form a cuboid = 5.5 × 10 × 3.5/22/7 × 0.875 × 0.875 × 0.2

Number of coins required to form a cuboid = 400

Hence, There are 400 silver coins melted to form a cuboid.