Ex.12.2 Q4 Exponents and Powers - NCERT Maths Class 8

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In a stack there are \(5\) books each of thickness \(20\, \rm{mm}\) and \(5\) paper sheets each of thickness \(0.016\,\rm{mm} \).

What is the total thickness of the stack?

 Video Solution
Exponents And Powers
Ex 12.2 | Question 4

Text Solution

What is known?

\(5\) books of \(20\rm{mm}\) thickness each. \(5\) paper sheets of \(0.016\rm{mm}\) thickness each.

What is unknown?

Total thickness of the stack


First find the total thickness of \(5\) books then find out total thickness of \(5\) paper sheets. Now find total thickness of stack by adding these two.


Thickness of each book \(= 20 \,\rm{mm}\)

Number of books per stack \(= 5\)

Thickness of \(5\) books \(=5\times20=10\,\rm{mm}\)

Thickness of each sheet\(=0.016\,\rm{mm}\)

Thickness of 5 paper sheets

\(=5\times 0.016=0.080\,\,\text{mm}\)

Total thickness of stack

\[ \begin{align} &= 100 +0.080 \\ & =100.080\;\rm{mm}\\ & =100.080 \\ & =1.0008\times10^2\,\rm{mm} \end{align} \]

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