SOLUTION: A man walks 30 minutes at an average speed of 3km /hr. He waits 10 minutes for a bus, which brings him back to starting point at 3.15pm. If he began his walk at 2.25 pm the same af

Algebra ->  Probability-and-statistics -> SOLUTION: A man walks 30 minutes at an average speed of 3km /hr. He waits 10 minutes for a bus, which brings him back to starting point at 3.15pm. If he began his walk at 2.25 pm the same af      Log On


   

Question 1024324: A man walks 30 minutes at an average speed of 3km /hr. He waits 10 minutes for a bus, which brings him back to starting point at 3.15pm. If he began his walk at 2.25 pm the same afternoon, find the average speed.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A man walks 30 minutes at an average speed of 3km /hr.
He waits 10 minutes for a bus, which brings him back to starting point at 3.15pm.
If he began his walk at 2.25 pm the same afternoon, find the average speed.
:
Find the total time of the trip: 3:15 - 2:25 = 50 min; 5%2F6 hrs
Find the distance to the bus stop: .5hrs * 3km/h = 1.5 km
Round trip = 3km and we know it took 5/6 hr
let a = the average speed of the trip
3%2Fa = 5%2F6
cross multiply
5a = 3 * 6
a = 18%2F5
a = 3.6 km/hr average speed for the whole trip