A logic problem by Ahmed Mahmoud
Indiana Jones needs to cross a flimsy rope bridge over a mile long gorge. It is so dark that it is impossible to cross the bridge without a flashlight. Furthermore, the bridge is so weak that it can only support the weight of two people. The party has only one flashlight, which has a weak beam so whenever two people cross, they are constrained to walk together, at the speed of the slower person. Indiana Jones can cross the bridge in 5 minutes. His girlfriend can cross in 10 minutes. His father needs 20 minutes, and his father’s side kick needs 25 minutes. They need to get everyone across safely in on hour to escape the bay guys. Can they do it?
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1 solution
Yes. Here is one possible solution. Let I; G; F and S denote Indiana Jones, Indiana Jones’ girlfriend, Indiana Jones’ father and the side-kick to cross the bridge. Step 1: I and G cross the bridge, total time is 10 min. Step 2: G returns to starting side of bridge, total time is 10 min. Step 3: F and S cross the bridge, total time is 25 min. Step 4: I returns to starting side of bridge, total time is 5 min. Step 5: I and G cross the bridge, total time is 10m in. Thus the total time is 60 min.