SOLUTION: A postman takes letters on foot from city A to city B at a speed of 4 miles/hr. If he walks at a speed of 5 miles/hr, then he reaches the city 7 minutes earlier. Find the distance

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Question 363813: A postman takes letters on foot from city A to city B at a speed of 4 miles/hr. If he walks at a speed of 5 miles/hr, then he reaches the city 7 minutes earlier. Find the distance between the two cities.

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
D=4T
D=5(T-7/60)
4T=5(T-7/60)
4T=5T-35/60
4T-5T=-35/60
-T=-35/60
T=35/60 35 MINUTES FOR THE 4MPH WALK.
D=4*35/60
D=140/60
D=2.33 MILES IS THE DISTANCE.
PROOF:
2.33=5(35/60-7/60)
2.33=5(28/60)
2.33=140/60
2.33=2.33