Ok, the table is as follows:
rate(mi/h) Time(h) Distance(mi)
To work 55 t 55t
To home 40 ?
The distance is going to equal the rate * time. Since we have the rate of the commute home, we need the time in order to find the distance. They give us a time of 1.25 hours for the round trip to work and back home. Since the time to work is t... then that means the time home is 1.25 - t. Since the distance is the rate * time, then
distance = 40(1.25 - t)
So the expression to fill in the missing distance is...
40(1.25 - t)