Timing!!

The five persons A, B, C, D and E were sleeping in a house and their enemies burnt it. The five persons were to escape through a tunnel. Only two people could go through the tunnel at a time. Moreover, it was totally dark and without a torch they could not proceed. They had only one torch. It means, two people should go out, and then one had to take the lamp inside and accompany another one out. Total 4 trips. It would take for A and B 5 minutes and C 10 minutes to come out. D would take 20 and E 25 minutes respectively to come through the tunnel, as one was hefty and another was old. This is an arithmetical problem and has no twists. How much minimum time it would take?

 Answer:
It would take 75 minutes for all the five to come out. A takes the three others with his torch. For taking B out, it takes 5 minutes, going back (5), bringing C (10), going back (5), bringing D (20), going back (5) and finally bringing back E(25).

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