You can Download KSEEB Solutions for Class 8 Maths Chapter 8 Comparing Quantities Ex 8.1 Questions and Answers helps you to revise the complete syllabus.
KSEEB Solutions for Class 8 Maths Chapter 8 Comparing Quantities Ex 8.1
Question 1.
Find the ratio of the following:
(a) Speed of a cycle 15 km per hour to the speed of scooter 30 km per hour.
(b) 5 m to 10 km.
(c) 50 paise to Rs. 5.
Solution:
(a) Speed of a cycle : speed of scooter
= 15 : 30
= 1 : 2
(b) 5m to 10 km
5 m : 10 × 1000 m
= 5 : 10,000
= 1 : 2000
(c) 50 paise to Rs. 5
50 p : 5 × 100 p
= 50 : 500
= 1 : 10
Question 2.
Convert the following ratios to percentages:
(a) 3 : 4
(b) 2 : 3
Solution:
(a) 3 : 4 = \(\frac{3}{4}\)
percentage = \(\frac{3}{4}\) × 100 = 75%
(b) 2 : 3 = \(\frac{2}{3}\)
percentage = \(\frac{2}{3}\) × 100 = 66\(\frac{2}{3}\) %
Question 3.
72% of 25 students are good in mathematics. How many are not good in mathematics?
Solution:
Total student = 25
Good in mathematics = 72%
Number of students good in mathematics = 72% of 25
= \(\frac{72}{100} \times 25\)
= 18
Number of students not good in mathematics = 25 – 18 = 7
Question 4.
A football team won 10 matches out of the total number of matches they played. If their win percentage was 40, then how many matches did they play in all?
Solution:
Let the total number of matches played = x
Total win = 10
% of matches won = 40%
∴ Number of matches won = 40% of x
⇒ 10 = \(\frac{40}{100} \times x\)
⇒ x = \(\frac{10 \times 100}{40}\)
⇒ x = 25
∴ No. of matches played 25
Question 5.
If Chameli has Rs. 600 left after spending 75% of her money, how much did she have in the beginning?
Solution:
Let the total money = Rs. x
Money spend = 75%
Money left (saving) = 100 – 75 = 25%
Money (saved) = Rs. 600
∴ Money saved = 25% of x
⇒ 600 = \(\frac{25}{100} \times x\)
⇒ x = \(\frac{600 \times 100}{25}\)
⇒ x = Rs. 2400
Question 6.
If 60% of people in a city like cricket, 30% like football, and the remaining like other games, then what percent of the people like other games? If the total number of people is 50 lakh, find the exact number who like each type of game.
Solution:
Let the total number of people in a city = 100
People like cricket = 60%
Number of people like cricket = 60% of 100
= \(\frac{60}{100} \times 100\)
= 60
Number of people like football = 30% of 100
= \(\frac{30}{100} \times 100\)
= 30
Number of people like other games = 100 – (60 + 30)
= 100 – 90
= 10
Total people in the city = 50 lakh
People who like cricket = 60% of 50 lakh
= \(\frac{60}{100} \times 50,00,000\)
= 30,00,000
People who like football = 30% of 50,00,000
= \(\frac{30}{100} \times 50,00,000\)
= 15,00,000
People who like other games = 50,00,000 – 30,00,000 + 15,00,000
= 50,00,000 – 45,00,000
= 5,00,000 or 5 lakh