(a) 30 minutes to 1.5 hour
1.5 hours = 1.5 x 60 = 90 minutes [∵ 1 hour = 60 minutes]
Now, ratio of 30 minutes to 1.5 hour = 30 minutes : 1.5 hour
⇒ 30 minutes : 90 minutes = 30/90 = 1/3 1:3

(b) 40 cm to 1.5 m
1.5 m = 1.5 x 100 cm = 150 cm [∵ 1 m = 100 cm]
Now, ratio of 40 cm to 1.5 m = 40 cm : 1.5 m
⇒ 40 cm : 150 cm = 40/150 = 4/15 = 4:15

(c) 55 paise to Re. 1
₹ 1 = 100 paise
Now, ratio of 55 paise to ₹1 = 55 paise : 100 paise
⇒ 55/100 = 11:20

(d) 500 ml to 2 litters
2 litres = 2 x 1000 ml = 2000 ml [∵1 litre = 1000 ml]
Now, ratio of 500 ml to 2 litres = 500 ml : 2 litres
⇒ 500 ml : 2000 ml = 500/2000 = 1/4 = 1:4

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