Q32. A cistern has three pipes A, B and C.Pipes A and B arc inlet pipes whereas C is an outlet pipe.Pipes A and B can fill the cistern separately in 3 hours and 4 hours respectively; while pipe C can empty the completely filled cistern 1 hour. If the pipes A, B and C are opened in order at 5, 6 and 7 a.m. respectively, at what time will the cistern be empty ?

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