Ex 2.5 Q2 Fractions and Decimals - NCERT Maths class 7
Question
Express as rupees using decimals:
i) \(7\) rupees \(7\) paise
ii) \(7\) rupees \(7\) paise
iii) \(7\) rupees \(7\) paise
iv) \(7\) rupees \(7\) paise
v) \(7\) rupees \(7\) paise
Text Solution
What is known?
Amount in paise.
What is unknown?
Amount in rupees.
Reasoning:
\(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees
Steps:
i) \(7\) paise
\(100\) paise \(=\) \(1\) rupees
\(1\) paise \(=\) \( \begin{align}\frac{1}{{100}}\end{align}\) rupees
\(7\) paise \(=\) \(7\) \(×\)\(\begin{align}\frac{1}{{100}}\end{align}\)rupees \(= 0.07\) rupees
ii) \(7\) rupees \(7\) paise
\(100\) paise \(=\) \(1\) rupees
\(1\) paise \(=\) \( \begin{align}\frac{1}{{100}}\end{align}\)rupees
\(7\) rupees \(7\) paise \(=\) \(7\) rupees \(+\) \(7\) paise
\(=\) \(7\) rupees \(+\) \(7\) \(×\)\( \begin{align}\frac{1}{{100}}\end{align}\)rupees
\(=\) \(7\) rupees \(+\) \(0.07\) rupees
\(=\) \(7.07\) rupees
iii) \(77\) rupees \(77\) paise
\(77\) rupees \(77\) paise \(=\) \(77\) rupees \(+\) \(77\) paise
\(=\) \(77\) rupees + \(77\) \(×\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees
( \(\because\)\(100\) paise \(=\) \(1\) rupees)
(\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\)rupees)
\(=\) \(77\) rupees \(+\) \(0.77\) rupees
\(=\) \(77.77\) rupees
iv) \(50\) paise
\(\therefore\) \(100\) paise \(=\) \(1\) rupees
\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(50\) paise \(=\) \(50\) \(×\)\( \begin{align}\frac{1}{{100}}\end{align}\)rupees
=> \(50\) paise \(=\) \(\begin{align}\frac{{50}}{{100}}\end{align}\)rupees
\(50\) paise \(=\) \(0.50\) rupees
v) \(235\) paise
\(\therefore\) \(100\) paise \(=\) \(1\) rupees
\(\therefore\) \(1\) paise \(=\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(235\) paise \(=\) \(235\) \(×\) \(\begin{align}\frac{1}{{100}}\end{align}\) rupees
\(235\) paise \(=\) \(\begin{align}\frac{{235}}{{100}}\end{align}\)rupees
\(235\)paise \(=\) \(2.35\) rupees