EXERCISE 8.1
1). Find the ratio of:
a) ₹ 5 to 50 paise
Ans: ₹ 1 = 100 paise
Then, ₹ 5 = 500 paise
= 500 : 50 = 500/50 = 10/1
= 10 : 1
b) 15 kg to 210 g
Ans: 1 kg = 1000 g
Then, 15 kg = 15000 g
= 15000 : 210 = 15000/210 = 500/7
c) 9 m to 27 cm
Ans: 1 m = 100 cm
Then, 9 m = 900 cm
= 900 : 27 = 900/27 = 100/3 = 100 : 3
d) 30 days to 36 hours Ans: 1 day = 24 hours
Then, 30 days = 30 × 24 = 720 hours
= 720 : 36 = 720/36 = 20/1
2). In a computer lab, there are 3 computers for every 6 students. How many computers will be needed for 24 students?
Ans:
Number of computers required for students = 3
So, number of computer required for 1 student = 3/6 = 1/2
So, the number of computers required for 24 students = 24 × 1/2 =12
∴ 12 computers will be needed for 24 students.
3). Population of Rajasthan = 570 lakhs and population of UP = 1660 lakhs.
Area of Rajasthan = 3 lakhs km2 and area of UP = 2 lakh km 2.
i) How many people are there per km2 in both these states?
Ans: Population of Rajasthan = 570 lakhs
Area of Rajasthan = 3 lakh km2
∴ Population of Rajasthan per km2 = (570 lakh)/(3 lakh km = 190 people per km2
Population of UP = 1660 lakhs
Area of UP = 2 lakh km2
Population of UP per km2 = (1660 lakhs)/(2 lakhs )
= 830 people per km2
ii) Which state is less populated?
Ans: By comparing both the states, we can clearly see that Rajasthan is less populated.