Exercise 2.2 - Chapter 2 Percentage and Simple Interest Term 3 7th Maths Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Ex $2.2$
Question 1.
Write each of the following percentage as decimal.
(i) $21 \%$
(ii) $93.1 \%$
(iii) $151 \%$
(iv) $65 \%$
(v) $0.64 \%$
Solution:
(i) $21 \%$
$=\frac{21}{100}=0.21$
(ii) $93.1 \%$
$=\frac{93.1}{100}=0.931$
(iii) $151 \%$
$=\frac{151}{100}=1.51$
(iv) $65 \%$
$=\frac{65}{100}=0.65$
(v) $0.64 \%$
$=\frac{0.64}{100}=0.0064$
 

Question 2 .
Convert each of the following decimal as percentage
(i) $0.282$

(ii) $1.51$
(iii) $1.09$
(iv) $0.71$
(v) $0.858$
Solution:
(i) $0.282$
$=0.282 \times 100 \%=\frac{282}{1000} \times 100 \%$
$=28.2 \%$
(ii) $1.51$ $=\frac{151}{100} \times 100 \%$ $=151 \%$
$\begin{aligned}
&=\frac{151}{100} \times 100 \% \\
&=151 \%
\end{aligned}$
(iii) $1.09$ $=\frac{109}{100} \times 100 \%$ $=109 \%$
$\begin{aligned}
&=\frac{109}{100} \times 100 \% \\
&=109 \%
\end{aligned}$
(iv) $0.71$
$\begin{aligned}
&=\frac{71}{100} \times 100 \% \\
&=71 \%
\end{aligned}$
(v) $0.858$
$\begin{aligned}
&=\frac{858}{1000} \times 100 \% \\
&=85.8 \%
\end{aligned}$

Question $3 .$
In an examination a student scored $75 \%$ of marks. Represent the given the percentage in decimal form?
Solution:
Student's Score $=75 \%=\frac{75}{100}=0.75$

Question $4 .$
In a village $70.5 \%$ people are literate. Express it as a decimal.
Solution:
Percentage of literate penple $=70.5 \%$
$\begin{aligned}
&=\frac{70.5}{100} \\
&=0.705
\end{aligned}$
 

Question $5 .$

Scoring rate of a batsman is $86 \%$. Write his strike rate as decimal.
Solution: 
Scoring rate of the batsman $=86 \%$
$\begin{aligned}
&=\frac{86}{100} \\
&=0.86
\end{aligned}$

Question 6 .
The height of a flag pole in school is $6.75 \mathrm{~m}$. Write it as percentage.
Solution:
Height of flag pole $=6.75 \mathrm{~m}$
$\begin{aligned}
&=\frac{675}{100} \\
&=6.75 \%
\end{aligned}$

Question $7 .$
The weights of two chemical substances are $20.34 \mathrm{~g}$ and $18.78 \mathrm{~g}$. Write the difference in percentage?
Solution:
Weight of substance $1=20.34 \mathrm{~g}$
Percentage of substance $1=\frac{2034}{100}=2034 \%$
Weight of substance $2=18.78 \mathrm{~g}$
Percentage of substance $2=\frac{1878}{100}=1878 \%$
Their difference $=2034-1878=156 \%$
 

Question 8 .
Find the percentage of shaded region in the following figure.

Solution:
Total region $=4$ parts
Shaded region $=1$ part
Fraction of shaded region $=\frac{1}{4}$
Percentage of shaded region $=\frac{1}{4} \times \frac{100}{100}$ $=\frac{1}{4} \times 100 \%$
$=25 \%$
 

Objective Type Questions
Question $1 .$
Decimal value of $142.5 \%$ is
(i) $1.425$
(ii) $0.1425$
(iii) $142.5$
(iv) $14.25$
Hint:
$\begin{aligned}
&142.5 \%=\frac{1425}{10} \% \\
&=\frac{1425}{10} \times \frac{1}{100} \\
&=1.425
\end{aligned}$
$=1.425$
(i) $1.425$
 

Question $2 .$
The percentage of $0.005$ is
(i) $0.005 \%$
(ii) $5 \%$
(iii) $0.5 \%$
(iv) $0.05 \%$
Hint:
$$
\begin{aligned}
&0.005=\frac{5}{1000} \\
&=\frac{5}{1000} \times \frac{100}{100} \\
&=0.5 \%
\end{aligned}
$$
Answer:
(iii) $0.5 \%$

Question $3 .$
The percentage of $4.7$ is
(i) $0.47 \%$
(ii) $4.7 \%$
(iii) $47 \%$
(iv) $470 \%$

Hint:
$\begin{aligned}
&4.7=\frac{47}{10} \\
&=\frac{47}{10} \times \frac{100}{100} \\
&=470 \%
\end{aligned}$
Answer:
(iv) $470 \%$