2. Say True or False.
(i) If the weight of 40 books is 8 kg, then the weight of 15 books is 3 kg.
Answer: True
(ii) A car travels 90 km in 3 hours with constant speed. It will travel 140 km in 5 hours at the same speed.
Answer: False
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:
2 hours reading no. of pages = 20
In 1 hour, reading = \( \frac{20}{2} \)
In 8 hours reading = \( \frac{20}{2} \times 8 = 80 \)
In 8 hours he read = 80 pages
In 1 hour, reading = \( \frac{20}{2} \)
In 8 hours reading = \( \frac{20}{2} \times 8 = 80 \)
In 8 hours he read = 80 pages
4. The cost of 15 chairs is ₹ 7500. Find the number of such chairs that can be purchased for ₹ 12,000?
Solution:
The cost of 15 chairs = ₹ 7500
Fractional form = \( \frac{15}{7500} \)
For Rs. 12,000 no. of chairs = \( \frac{15}{7500} \times 12000 \)
= \( \frac{120}{5} = 24 \)
For ₹ 12,000 no. of chairs = 24 chairs.
Fractional form = \( \frac{15}{7500} \)
For Rs. 12,000 no. of chairs = \( \frac{15}{7500} \times 12000 \)
= \( \frac{120}{5} = 24 \)
For ₹ 12,000 no. of chairs = 24 chairs.
5. A car covers a distance of 125 km in 5 kg of LP Gas. How much distance will it cover in 3 kg of LP Gas?
Solution:
A car covers 125 km by using gas of = 5 kg
For 1 kg gas = \( \frac{125}{5} \)
For 3 kg gas = \( \frac{125}{5} \times 3 \)
= 75 km
The distance covers for 3 kg gas = 75 km
For 1 kg gas = \( \frac{125}{5} \)
For 3 kg gas = \( \frac{125}{5} \times 3 \)
= 75 km
The distance covers for 3 kg gas = 75 km
6. Cholan walks 6 km in 1 hour at constant speed. Find the distance covered by him in 20 minutes at the same speed.
Solution:
Cholan walks 6 km in 1 hour = 60 minutes
For 1 minute = \( \frac{6}{60} \)
For 20 minutes = \( \frac{6}{60} \times 20 \)
For 20 minutes he walks = 2 km
For 1 minute = \( \frac{6}{60} \)
For 20 minutes = \( \frac{6}{60} \times 20 \)
For 20 minutes he walks = 2 km
7. The number of correct answers given by Kaarmugilan and Kavitha in a quiz competition are 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:
Kaarmugilan : Kavitha = 10 : 11
Total score = 84 points
Total parts = 10 + 11 = 21
For 1 part = \( \frac{84}{21} = 4 \) points
Kavitha Score = 11 parts
11 parts = \( 11 \times 4 = 44 \) points
Kavitha Scored = 44 points.
Total score = 84 points
Total parts = 10 + 11 = 21
For 1 part = \( \frac{84}{21} = 4 \) points
Kavitha Score = 11 parts
11 parts = \( 11 \times 4 = 44 \) points
Kavitha Scored = 44 points.
8. Karmegan 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:
Karmegan run rate = 54 : 9
For one over = \( \frac{54}{9} = 6 \)
Asif run rate = 77 : 11
For one over = \( \frac{77}{11} = 7 \)
i.e., 7 > 6
Asif run rate is better than Karmegan.
For one over = \( \frac{54}{9} = 6 \)
Asif run rate = 77 : 11
For one over = \( \frac{77}{11} = 7 \)
i.e., 7 > 6
Asif run rate is better than Karmegan.
9. You purchase 6 apples for ₹ 90 and your friend purchases 5 apples for ₹ 70. Whose purchase is better?
Solution:
My purchase 6 apples = Rs. 90 (Cost per apple = \( \frac{90}{6} = 15 \))
Friend purchase 5 apples = Rs. 70 (Cost per apple = \( \frac{70}{5} = 14 \))
Comparison: 15 > 14
My friend’s rate of purchase is better than mine (as it is cheaper).
Friend purchase 5 apples = Rs. 70 (Cost per apple = \( \frac{70}{5} = 14 \))
Comparison: 15 > 14
My friend’s rate of purchase is better than mine (as it is cheaper).
OBJECTIVE TYPE QUESTIONS
10. If a barbie doll costs ₹ 90, then the cost of 3 such dolls is ₹ ___________.
Answer: (b) 270
11. If 8 oranges cost ₹ 56, then the cost of 5 oranges is ₹ ___________.
Answer: (c) 35
12. If a man walks 2 km in 15 minutes, then he will walk ___________ km in 45 minutes.
Answer: (c) 6 km