Question 986987
You walk at an average of 3.2 miles per hour on the way to school, and at an average of 4 miles per hour on the way home.
The total walking time is 18 minutes. 
 How far away is the school?
 Round your answer to the nearest hundredth of a mile.
:
Since we are dealing in mph, change 18 min to hrs; 18/60 .3 hrs
let d = the one way distance
write time equation; time = dist/speed
To time + return time = .3 hrs
{{{d/3.2}}} + {{{d/4}}} = .3
clear denominators, multiply equation by 32, cancel the denominators
10d + 8d = .3(32)
18d = 9.6
d = 9.6/18
d = .53 mi to the school
:
;
Confirm this, find the actual time each way
.533/3.2 = .167 hrs
.533/4.0 = .133 hrs
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total time: .3 hrs