EXERCISE 10A
of the following ratios in the simplest form:
(ii) 84 paise to 3 (iii) 4 kg to 750 g
56
to 6 kg
(v) 48 minutes to 1 hour (vi) 2.4 km to 900 m
ch of the following ratios in the simplest form:
(ii) 324 : 144
(iii) 85 : 561
84
(v) 186 : 403
(vi) 777 : 1147
f the following ratios in the simplest form:
16.80
ii) 3 weeks : 30 days (iii) 3 m 5 cm : 35 cm
2 hours 40 min (v) 1 L 35 mL: 270 mL. (vi) 4 kg: 2 kg 500 g
d his wife are both school teachers and earn 16800 and 10500 per month
Find the ratio of
i's income to his wife's income;
ai's income to her husband's income;
i's income to the total income of the two.
15300 and saves 1224 per month. Find the ratio of
(ii) his income and expenditure;
diture and com
ne and savings;
Answers
Question 1:
Find each of the following ratios in the simplest form:
(i) 24 to 56
(ii) 84 paise to Rs 3
(iii) 4 kg to 750 g
(iv) 1.8 kg to 6 kg
(v) 48 minutes to 1 hour
(vi) 2.4 km to 900 m
ANSWER:
(i) 24:56 = 24 = 24 ÷ 8 = 3
56 56 ÷ 8 7
As the H.C.F. of 3 and 7 is 1, the simplest form of 24:56 is 3:7.
(ii) 84 paise to Rs 3 = Rs 0.84 to R. 3 = 0.84 = 0.84 ÷ 3 = 0.28 = 28 = 28 ÷ 4 = 7
3 3 ÷ 3 1 100 100 ÷ 4 25
As the H.C.F. of 7 and 25 is 1, the simplest form of 0.84:3 is 7:25.
(iii) 4 kg:750 g = 4000 g:750 g = 4000 ÷ 250 = 16
750 ÷ 250 3
As the H.C.F. of 16 and 3 is 1, the simplest form of 4000:750 is 16:3.
(iv) 1.8 kg:6 kg = 1.8 = 18 = 18 ÷ 6 = 3
6 60 60 ÷ 6 10
As the H.C.F. of 3 and 10 is 1, the simplest form of 1.8:6 is 3:1.
(v) 48 minutes to 1 hour = 48 minutes to 60 minutes = 48:60 = 48 ÷ 12 = 4
60 ÷ 12 5
As the H.C.F. of 4 and 5 is 1, the simplest form of 48:60 is 4:5.
(vi) 2.4 km to 900 m = 2400m:900m = 2400 = 24 = 24 ÷ 3 = 8
900 9 9 ÷ 3 3
As the H.C.F. of 8 and 3 is 1, the simplest form of 2400:900 is 8:3.
Page No 152:
Question 2:
Express each of the following ratios in the simplest form:
(i) 36 : 90
(ii) 324 : 144
(iii) 85 : 561
(iv) 480 : 384
(v) 186 : 403
(vi) 777 : 1147
ANSWER:
(i) 36:90 = 36 = 36 ÷ 18 = 2 (As the H.C.F. of 36 and 90 is 18.)
90 90 ÷ 18 5
Since the H.C.F. of 2 and 5 is 1, the simplest form of 36:90 is 2:5.
(ii) 324:144 = 324 = 324 ÷ 36 = 9 (As the H.C.F. of 324 and 144 is 36.)
144 144 ÷ 36 4
Since the H.C.F. of 9 and 4 is 1, the simplest form of 324:144 is 9:4.
(iii) 85:561 = 85 = 85 ÷ 17 = 5 (As the H.C.F. of 85 and 561 is 17.)
561 561 ÷ 17 33
Since the H.C.F. of 5 and 33 is 1, the simplest form of 85:561 is 5:33.
(iv) 480:384 = 480 = 480 ÷ 96 = 5 (As the H.C.F. of 480 and 384 is 96.)
384 384 ÷ 96 4
Since the H.C.F. of 5 and 4 is 1, the simplest form of 480:384 is 5:4.
(v) 186:403 = 186 = 186 ÷ 31 = 6 (As the H.C.F. of 186 and 403 is 31.)
403 403 ÷ 31 13
Since the H.C.F. of 6 and 13 is 1, the simplest form of 186:403 is 6:13.
(vi) 777:1147 = 777 ÷ 37 = 21 (As the H.C.F. of 777 and 1147 is 37.)
1147 ÷ 37 31
Since the H.C.F. of 21 and 31 is 1, the simplest form of 777:1147 is 21:31.
Page No 152:
Question 3:
Write each of the following ratios in the simplest form:
(i) Rs 6.30 : Rs 16.80
(ii) 3 weeks : 30 days
(iii) 3 m 5 cm : 35 cm
(iv) 48 min : 2 hours 40 min
(v) 1 L 35 mL : 270 mL
(vi) 4 kg : 2 kg 500 g
ANSWER:
(i) Rs 6.30:Rs 16.80
6.30 = 63 = 63 ÷ 21 = 3 (H.C.F. of 63 and 168 is 21.)
16.80 168 168 ÷ 21 8
Ratio = 3 : 8
(ii)3 weeks:30 days = 21days:30 days (1 week = 7 days)
21 = 21 ÷ 3 = 7 (H.C.F. of 21 and 30 is 3.)
30 30 ÷ 3 10
Ratio = 7 : 10
(iii) 3 m 5 cm:35 cm = 305 cm:35 cm (1 m = 100 cm)
305 = 305 ÷ 5 = 61 (H.C.F. of 305 and 35 is 5.)
35 35 ÷ 5 7
Ratio = 61:7
(iv) 48 min:2 hours 40 min = 48 min:160 min (1 hour = 60 mins)
48 = 48 ÷ 16 = 3 (H.C.F. of 48 and 160 is 16.)
160 160 ÷ 16 10
Ratio = 3:10
(v) 1 L 35 mL:270 mL = 1035 mL:270 mL (1 L = 1000 mL)
1035 = 1035 ÷ 45 = 23 (H.C.F. of 1035 and 270 is 45.)
270 270 ÷ 45 6
Ratio = 23:6
(vi) 4 kg:2 kg 500 g = 4000 g:2500 g (1 kg= 1000 g)
4000 = 40 = 40 ÷ 5 = 8 (H.C.F. of 40 and 25 is 5.)
2500 25 25 ÷ 5 5
Ratio = 8:5
Question 4:
Mr Sahai and his wife are both school teachers and earn Rs 16800 and Rs 10500 per month respectively. Find the ratio of
(i) Mr Sahai's income to his wife's income;
(ii) Mrs Sahai's income to her husband's income;
(iii) Mr Sahai's income to the total income of the two.
ANSWER:
Mr Sahai's earning = Rs 16800
Mrs Sahai's earning = Rs 10500
(i) Ratio = 16800:10500 = 168:105 = 168 ÷ 21 = 8 (H.C.F. of 168 and 105 is 21.)
105 ÷ 21 5
Mr Sahai's income:Mrs Sahai's income = 8:5
(ii)Ratio = 10500:16800 = 105:168 = 105 ÷ 21 = 5 (H.C.F. of 168 and 105 is 21.)
168 ÷ 21 8
Mrs Sahai's income:Mr Sahai's income = 5:8
(iii) Total income = 16800 + 10500 = Rs 27300
Ratio = 16800:27300 = 168:273 = 168 = 168 ÷ 21 = 8 (H.C.F. of 168 and 273 is 21.)
273 273 ÷ 21 13
Mrs Sahai's income:Total income = 8:13