Question

Mary logged into work at 8:10 am and logged out at 3:45 pm. How many hours did she work? (Her employer rounds to the nearest quarter hour.)

Answer 1

first we count how many hours is inbetween 8 and 3 which is 7

then subtract 10 for the first time

6:50 then add 45 for the second time

7:35

round down so she worked 7 1/2 hours

Answer 2

Mary worked 7 and a half hours.

Explanation:

The easiest way to solve this is converting to the 24 hours metric.

In this metric, 8:10 am is 8h, 10 min.

3:45 pm is 12+3 = 15h, 45 min.

Rounded to the nearest quarter hour, Mary worked 15-8 = 7h, 45-10 = 35 min, Mary worked 7 and a half hours.