Class 6 - Mathematics
Chapter - Comparing Quantities : Exercise 8.1
Top Block 1
Question: 1. Find the ratio of:
(a) Rs. 5 to 50 paise
(b) 15 kg to 210 g
(c) 9 m to 27 cm
(d) 30 days to 36 hours
Answer :
To find ratios, both quantities should be in same unit.
(a) Rs. 5 to 50 paise
⇒ 5 x 100 paise to 50 paise
[∵ Rs. 1 = 100 paise]
⇒ 500 paise to 50 paise
Thus, the ratio is = 500⁄50 = 10⁄1 = 10 : 1
(b) 15 kg to 210 g
⇒ 15 x 1000 g to 210 g [ ∵ 1 kg = 1000 g]
⇒ 15000 g to 210 g
Thus, the ratio is = 1500⁄210 = 500⁄7 = 500 : 7
(c) 9 m to 27 cm
⇒ 9 x 100 cm to 27 cm [ ∵ 1 m = 100 cm]
⇒ 900 cm to 27 cm
Thus, the ratio is = 900⁄27 = 100⁄1 = 100 : 3
(d) 30 days to 36 hours
⇒ 30 x 24 hours to 36 hours [ ∵ 1 day = 24 hours]
⇒ 720 hours to 36 hours
Thus, the ratio is = 720⁄36 = 20⁄1 = 20 : 1
Question: 2.In a computer lab, there are 3 computers for every 6 students. How many computers will be needed for 24 students?
Answer :
(a) 0.65 = 65⁄100 × 100% = 65%
(b) 0.02 = 2⁄100 × 100% = 2%
Mddle block 1
Question: 3.Population of Rajasthan = 570 lakhs and population of U.P. = 1660 lakhs. Area of Rajasthan = 3 lakh km2 and area of U.P. = 2 lakh km2.
(i) How many people are there per km2 in both states?
(ii) Which state is less populated?
Answer :
(i) People present per km2 = Population⁄Area
In Rajasthan = (570 lakhs )⁄(3 lakh per km2) = 190 people km2
In U.P. = (1660 lakhs)⁄(2 lakh per km2) = 830 people per km2
(ii) Rajasthan is less populated.