A man in a bus travels 4 miles in 3 minutes. Then he gets out of the bus and walks back to his starting point, taking 9/20 hour. What was his average speed for the whole trip?
I know the answer is 16 ... how do you get there is my question. (show work)
2007-03-21 03:34:54 · 5 answers · asked by Michael E 2 in Science & Mathematics ➔ Mathematics
Well he travels 8 miles round trip.
9/20 of an hour is 9 * 3 = 27 minutes. Add 3 to that, and he spends a total of 30 minutes traveling.
8 miles in 30 minutes is 8 miles in 0.5 hours.
Since the expression is asking for miles per hours (or miles/hour), you get (8 miles) / (0.5 hours) = 16 mph
2007-03-21 03:42:02 · answer #1 · answered by Bhajun Singh 4 · 2⤊ 0⤋
Total distance = 4+4= 8 miles
Total Time = 3+9/20*60
=3+27
=30 minutes
=30/60 hrs
=0.5 hrs
Therefore,
Average speed= Total Distance/ Total Time
=8/0.5
=16 miles /hr
2007-03-21 10:46:35 · answer #2 · answered by Bubblez 3 · 1⤊ 0⤋
9/20 of an hour = 9 times 3 minutes (20th of an hour) = 27 minutes.
4 miles in 3 minutes plus 4 miles back in 27 minutes = 8 miles in 30 minutes which is 1/2 of an hour. So 2 times 30 minutes is an hour and 2 times 8 miles is how far he would have traveled in an hour = 16 Miles Per Hour.
2007-03-21 10:42:56 · answer #3 · answered by a0_allears 2 · 0⤊ 1⤋
3 min to travel out (given).
60*9/20 = 27 min to travel back.
3 min + 27 min = 30 min.
4 mi out + 4 mi back = 8 mi travelled.
8 miles in 30min, 2*8 mi in 60 min, 16 mph.
2007-03-21 10:39:28 · answer #4 · answered by Anonymous · 2⤊ 0⤋
AVerage = total distance/total time = (4+4)/(27+3) = 8/30 = 0.1667 miles/min= 0.1667*60= 16mph.
2007-03-21 10:46:36 · answer #5 · answered by The exclamation mark 6 · 0⤊ 1⤋