i) 25 minutes to 55 minutes
Given 25 minutes to 55 minutes = 25 : 55
HCF of 25 and 55 is 5 = 25 ÷ 5 : 55 ÷ 5 (Divide each term by 5)
∴ Required ratio = 5:11
ii) 45 seconds to 30 minutes
Given 45 seconds to 30 minutes.
To write the given ratio in the simplest form.
First convert the two terms into same units.
1 minute = 60 seconds
30 minutes = 30 × 60 = 1800 seconds
Then, find the HCF of two terms and divide them by their HCF.
HCF of 45 and 1800 is 45.
= 45 ÷ 45 : 1800 ÷ 45 (divide each term by 45)
∴ Required ratio = 1 : 40