Ninety minutes are in an hour and a half
There are 30 minutes in half an hour and 15 minutes in a quarter of an hour
30 minutes equal half an hour.
30 minutes = half an hour, because 60 minutes are one hour.
30 minutes are in half an hour.
There are 60 minutes in an hour therefore the number of minutes in half an hour is 60x0.5=30.