Question 310001
His round trip travel time was 2 1/2 hours.
 If the bus averaged 45 miles per hour going to his grandmother’s house and 30
 miles per hour on the return trip,
 how many miles from his grandmother’s house does Jermaine live?
:
Let d = distance from grandma's house
:
Write a time equation; time = dist/speed
:
"to trip" + return trip = 2.5 hrs
{{{d/45}}} + {{{d/30}}} = 2.5
multiply equation by 90 to get rid of the denominators, results
2d + 3d = 2.5(90)
5d = 225
d = {{{225/5}}}
d = 45 mi to grandma's 
:
;
Check solution by finding the times
45/45 = 1.0
45/30 = 1.5
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total: 2.5