Ex 2.2 Q5 Fractions-and-Decimals-Solutions NCERT Maths Class 7

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Question

 Find: -

\(\begin{align}\left( {\rm{a}} \right)\,\,\frac{1}{2}{\rm{ of \quad i) }}24\quad{\rm{ ii) }}\;46\end{align}\)                                    \(\begin{align}\left( {\text{b}} \right)\,\,\frac{2}{3}{\text{ of       i) }}\;18\;\quad{\text{ ii) }}\;27\end{align}\)

\(\begin{align}\left( {\text{c}} \right)\,\,\frac{3}{4}{\text{ of        i) }}\,16\;\quad{\text{ ii) }}\;36\end{align}\)                           \(\begin{align}\left( {\text{d}} \right)\frac{4}{5}{\text{ of       i }})\,20\;\quad {\text{ ii) }}\;35\end{align}\)


 

Text Solution

What is known?

Fraction and whole.

What is unknown?

Part of following whole according to given fraction.

Reasoning:

Multiple whole by fraction.

Steps:

(a) \(\begin{align}{{\rm{ (i) }}\frac{1}{2}{\rm{ of }}\;24 = \frac{1}{2} \times \frac{{24}}{1} = \frac{{24}}{2} = 12}\\
\end{align}\)

\(\begin{align}{\rm{ (ii) }}\frac{1}{2}{\rm{ of }}\;46 = \frac{1}{2} \times \frac{{46}}{1} = \frac{{46}}{2} = 23\end{align}\)

(b) \(\begin{align}{{\rm{ (i) }}\frac{2}{3}{\rm{ of }}\;18 = \frac{2}{3} \times \frac{{18}}{1} = 2 \times 6 = 12}\\\end{align}\)

\(\begin{align}{\rm{(ii)}}\frac{2}{3}{\rm{ of }}\;27 = \frac{2}{3} \times \frac{{27}}{1} = 2 \times 9 = 18\end{align}\)

(c) \(\begin{align}\left( {\rm{i}} \right)\,\,\frac{3}{4}{\rm{ of }}\;16 = \frac{3}{4} \times \frac{{16}}{1} = 3 \times 4 = 12\end{align}\)

\(\begin{align}\left( {{\rm{ii}}} \right)\frac{3}{4}{\rm{ of }}\;36 = \frac{3}{4} \times \frac{{36}}{1} = 3 \times 9 = 27\end{align}\)

(d) \(\begin{align}\left( {\rm{i}} \right)\,\,\frac{4}{5}{\rm{ of }}\;20 = \frac{4}{5} \times \frac{{20}}{1} = 4 \times 4 = 16\end{align}\)

(ii) \(\begin{align}\frac{4}{5}{\rm{ of }}\;35 = \frac{4}{5} \times \frac{{35}}{1} = 4 \times 7 = 28\end{align}\)

  
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