**Ex $3.4$
Question $1 .$**

Fill in the blanks.

(i) If the cost of 3 pens is ₹ 18 , then the cost of 5 pens is

(ii) If Karkuzhali earns ₹ 1800 in 15 days, then she earns ₹ 3000 in days

Solution:

(i) ₹ 30

Hint: $5 \times \frac{18}{3}=5 \times 6=₹ 30$

(ii) 25 Days

Hint:

$\begin{aligned}

&\frac{1800}{3000}=\frac{15}{x} \\

&\Rightarrow \mathrm{x}=\frac{15 \times 3000}{1800}=25 \text { days }

\end{aligned}$

**Question 2 .**

Say True or False.

(i) If the weight of 40 books is $8 \mathrm{~kg}$, then the weight of 15 books is $3 \mathrm{~kg}$.

(ii) A car travels $90 \mathrm{~km}$ in 3 hours with constant speed, It will travel $140 \mathrm{~km}$ in 5 hours at the same speed.

Solution:

(i) True

(ii) False

**Question $3 .$**

If a person reads 20 pages of a book in 2 hours, how many pages will he read in 8 hours at the same speed.

Solution:

Pages read in 2 hours $=20$

Then pages read in 1 hour $=\frac{20}{2}=10$ pages.

Pages will be read in 8 hours $=8 \times 10=80$ pages.

Number of pages will be read in 8 hrs $=80$ pages

**Question 4 .**

The cost of 15 chairs is Rs 7500 . Find the number of such chairs that can be purchased for Rs $12000 ?$

Solution:

Cost of 15 chairs $=$ Rs 7500

Cost of 1 chair $=$ Rs $\frac{7500}{15}=$ Rs 500

Numher of chairs that can he purchased for Rs $12000=\frac{12000}{500}$

$=24$ chairs

**Question 5 .**

A car covers a distance of $125 \mathrm{~km}$ in $5 \mathrm{~kg}$ of LP Gas. How much distance will it cover in $3 \mathrm{~kg}$ of LP Gas?

Solution:

With $5 \mathrm{~kg}$ LP Gas distance covered $=125 \mathrm{~km}$

With $1 \mathrm{~kg}$ LP Gas distance covered $=\frac{125}{5}=25 \mathrm{~km}$

With $3 \mathrm{~kg}$ LP Gas distance covered $=25 \times 3=75 \mathrm{~km}$.

$75 \mathrm{~km}$ can be covered with $3 \mathrm{~kg}$ LP Gas.

**Question 6 .**

Cholan walks $6 \mathrm{~km}$ in 1 hour at constant speed. Find the distance covered by him in $20 \mathrm{minutes}$ at the same speed.

Solution:

In 1 hour ( 60 minutes), distance covered $=6 \mathrm{~km}$

In 1 minute, distance covered $=\frac{6 k m}{60 m i n}=\frac{6000 m}{60}$

$=100 \mathrm{~m}$

In 20 minutes, distance covered $=20 \times 100 \mathrm{~m}=2000 \mathrm{~m}=2 \mathrm{~km}$

**Question 7 .**

The number of correct answers given by Kaarmugilan and Kavitha in a quiz competition is in the ratio $10: 11 .$ If they had scored a total of 84 points in the competition, then how many points did Kavitha get?

Solution:

Correct answers given by Kaarmugilan and Kavitha are in the ratio $10: 11$

Total of 84 points will be divided into $10+11=21$ equal parts

Points scored by Kavitha $=\frac{11}{21} \times 84=44$ points

Kavitha scored 44 points in the quiz.

**Question 8 .**

Karmegam made 54 runs in 9 overs and Asif made 77 runs in 11 overs. Whose run rate is better?

(run rate $=$ ratio of runs to overs)

Solution:

Karmegam Runs made in 9 overs $=54$

Runs made in 1 over $=\frac{54}{9}=6$ runs

Asif Runs made in 11 overs $=77$ Runs made in 1 over $=\frac{77}{11}=7$ runs

$\therefore$ Asif's run rate is better than Karmegam.

**Question $9 .$**

You purchase 6 apples for ₹ 90 and your Mend purchases 5 apples for ₹ 70 . Whose purchase is better?

Solution:

In my purchase cost of 6 apples $=₹ 90$

Cost of 1 apple $=\frac{90}{6}=₹ 15$

In my friend's purchase cost of 5 apples $=₹ 70$

Cost of 1 apple $=\frac{70}{5}=₹ 14$

My friend buy for lower prize.

My friend's purchase is a better buy.

**Objective Type Questions
Question 10 .**

If a Barbie doll costs Rs 90 , then the cost of 3 such dolls is Rs.......

(a) 260

(b) 270

(c) 30

(d) 93

Solution:

(b) 270

**Question 11 .**

If 8 oranges cost ₹ 56 , then the cost of 5 oranges is ₹

(a) 42

(b) 48

(c) 35

(d) 24

Solution:

(c) 35

**Question 12 .**

If a man walks $2 \mathrm{~km}$ in 15 minutes, then he will walk $\mathrm{km}$ in 45 minutes.

(a) 10

(b) 8

(c) 6

(d) 12

Solution:

(c) 6