Haryana State Board HBSE 8th Class Maths Solutions Chapter 8 Comparing Quantities Ex 8.1 Textbook Exercise Questions and Answers.
Haryana Board 8th Class Maths Solutions Chapter 8 Comparing Quantities Exercise 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) Ratio of speed of cycle to speed of scooter = 15 : 30 = 1 : 2
(b) Ratio of 5 m to 10 km
⇒ Ratio of 5 m to 100000 m = 5 : 100000 = 1 : 20000
(c) Ratio of 50 paise to Rs. 5
⇒ Ratio of 50 paise to 500 paise
= 50 : 500 = 1 : 10.
Question 2.
Convert the following ratios to percentages.
(а) 3 : 4
(b) 2 : 3
Solution:
(a) Ratio = 3 : 4
Fraction = \(\frac{3}{4}\)
Percentage = \(\frac{3 \times 25}{4 \times 25}\) = \(\frac{75}{100}\) = 75%
(b) Ratio = 2 : 3
Fraction = \(\frac{2}{3}\)
Percentage = \(\frac{2}{3} \times \frac{100}{100}\) = \(\frac{200}{3} \times \frac{1}{100}\)
= 66\(\frac{2}{3}\)%.
Question 3.
72% of 25 students are good in mathematics. How many are not good in mathematics ?
Solution:
Total percent good in mathematics and not good in mathematics = 100
72 + percentage of student not good in mathematics = 100
∴ Percentage of students not good in mathematics = 100 – 72 = 28
So number of students hot good in mathematics = 28% of 25
= \(\frac{28}{100}\) × 25 = 7 students.
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 by football team be x their win was 40%.
So, 40% of x = 10
\(\frac{40}{100}\) × x = 10
x = \(\frac{10 \times 100}{40}\) = 25
Number of played matches = 25.
Question 5.
If Chameli had Rs. 600 left after spending 75% of her money, how much did she have in the beginning ?
Solution:
Let she had Rs. x in the beginning
Chameli spent 75% of her money.
So she left 100 – 75 = 25% of her moriey.
So, 25% of x = Rs. 600
\(\frac{25}{100}\) × x = 600
x = \(\frac{600 \times 100}{25}\) = 2400
Chameli had Rs. 2400 in the beginning.
Question 6.
If 60% 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 are .50 lakh, find the exact number who like each type of game.
Solution:
Total percent = 100
60% people like cricket
30% people like football
remaining like other game
So 100 – (60 + 30) = 10% like other game.
Total no. of people = 50 lakh
No. of people like cricket
= 60% of 50 lakh
= \(\frac{60}{100}\) × 50 lakh = 30 lakh
No. of people like football
= 30% of 50 lakh on
= \(\frac{30}{100}\) × 50 lakh = 15 lakh
No. of people like other game
= 10% of 50 .lakh
= \(\frac{10}{100}\) × 50 lakh = 5 lakh.