Problema Solution
A bus with 12 basketball players broke down in a town 20 miles from the basketball tournament. The coachs car was available but could carry only 4 players at a time. Also it could only travel 20 miles per hour because of traffic. The players said they could walk at 4 miles per hour when they were not riding. Suppose the coach took 4 of them part way, came back for 4 more and took them part way, and then came back for the last 4. How could they all get to their scheduled basketball tournament at the same time?
Answer provided by our tutors
| 4 miles | 4 miles | 4 miles | 4 miles | 4 miles |
A---------B---------C----------D----------E---------F
coach picks up first 4 and drops them from A to D = 12 miles
coach then drives from D to B = 8 miles
coach picks up the next four and drives from B to E = 12 miles
coach then drives back from E to C = 8 miles
coach picks up last four and travels from C to F = 12 miles
so all in all he travels 52 miles in the car.
now just to clarify:
the first 4: drove in the car 12 miles which took them 12/20 hours and walked 8 miles which took 2 hours = 2 12/20 hours
the second 4 : walked 4 miles which took them 1 hour drove 12 miles which took them 12/20 hours and walked another 4 miles which another 1 hour = 2 12/20 hours
the third 4: they walked 8 miles which took them 2 hours drove 12 miles which took them 12/20 hours = 2 12/20 hours
Thus all of them arrived at the scheduled basketball tournament at the same time - after 2 12/20 = 2.6 hours.