There is a few ways to get the result. Lets try this. First calculate how many minutes are in the 5 hours. 60min*5=300min - in 5 hours Now, knowing that quarter is 15min we can divide 300 by 15 to get the result, so 300:15=20 - its the result.
i would do this with a proportion. we know 4 quarter hours are in 1 hour, so how many are in 5? 4/1 = x/5 cross multiply 1x=45 x=20 there are 20 quarter hours in 5 hours.
