4 space organisms (A, B, C and D) need to move from the shuttle to the space station. A takes 1 minute to cross over in either direction B takes 2 “ ” C takes 4 “ ” D takes 5 “ ” There is only one oxygen pack and it will support two space organisms at a time. So two can cross over at once and this will take the time of the slowest space organism (and then one returns for the next space organism). AB → cross (2 minutes) A ← returns (1 minute) AC → cross (4 minutes) A ← returns (1 minute) AD → cross (5 minutes) so all space organisms cross in 13 minutes. PROBLEM – there is only 12 minutes of oxygen, what can they do? Try to solve it here.
