The Jones family drove to Disneyland at 50mph and returned o

The Jones family drove to Disneyland at 50mph and returned on the same route at 40mph. Find the distance to Disneyland if the total driving time was 7.2hrs.

Solution

Distance(d)=rate(r)*time(t) -->d=rt
The distance to Disneyland is the same as the distance from Disneyland.
:
The rate to Disney is: 50mph
The time to disney is:t
Therefore the distance to Disney is: 50t
:
The rate from Disney is: 40mph
the time is the rest of the 7.2 hours of time not going to Disney: 7.2-t
Therefore, the distance from Disney is:40(7.2-t)
:
Since the two distances are equal:
50t=40(7.2-t)
50t=288-40t
50t+40t=288-40t+40t
90t=288
90t/90=288/90
t=3.2 hr
:
To find the distance, substitute t=3.2 into the distance to Disney equation of 50t:
d=50(3.2)=160 mi.