First you have to find out what is 1/4 of an hour which in order to find you have to multiply 1/4 by 60 because it has 60 mins in an hour. You now have 15 mins and we already know there are 60 mins so we divide 60 by 15 which give you 4 then you multiply 1/5 by 4 which gives you 4/5 or 0.8.
