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# A Metal Parallelopiped of Measures 16 Cm X 11 Cm X 10 Cm Was Melted to Make Coins. How Many Coins Were Made If the Thickness and Diameter of Each Coin Was 2 Mm and 2 Cm Respectively ? - Geometry

ConceptIntroduction of Surface Areas and Volumes

#### Question

A metal parallelopiped of measures 16 cm x 11 cm x 10 cm was melted to make coins. How many coins were made if the thickness and diameter of each coin were 2 mm and 2 cm respectively?

#### Solution

Radius of each coin, r =  $\frac{2}{2}$ = 1 cm
Thickness of each coin, h = 2 mm = $\frac{2}{10}$= 0.2 cm   (1 cm = 10 mm)
Let the number of coins made be n.
It is given that a metal parallelopiped is melted to make the coins.
∴ n × Volume of metal in each coin = Volume of the metal parallelopiped

$\Rightarrow n = \frac{\text{ Volume of the metal parallelopiped } }{\text{ Volume of metal in each coin } }$
$\Rightarrow n = \frac{16 \times 11 \times 10}{\pi r^2 h}$
$\Rightarrow n = \frac{16 \times 11 \times 10}{\frac{22}{7} \times \left( 1 \right)^2 \times 0 . 2} = 2800$

Thus, the number of coins made are 2800.

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#### APPEARS IN

Balbharati Solution for Balbharati Class 10 Mathematics 2 Geometry (2018 to Current)
Chapter 7: Mensuration
Practice set 7.4 | Q: 4 | Page no. 161

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Solution A Metal Parallelopiped of Measures 16 Cm X 11 Cm X 10 Cm Was Melted to Make Coins. How Many Coins Were Made If the Thickness and Diameter of Each Coin Was 2 Mm and 2 Cm Respectively ? Concept: Introduction of Surface Areas and Volumes.
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