The road from A to B has an uphill section and a flat section. If you keep going uphill at 3km per hour, on the flat road at 4km per hour, and downhill at 5km per hour, then it takes 54 minutes to travel from A to B. , It takes 42 minutes to go from place B to place A. How much is the whole journey from place A to place B?
从甲地到乙地的路有一段上坡与一段平路，如果保持上坡每小时走3km，平路每小时走4km，下坡每小时走5km，那么从甲地到乙地需54分，从乙地到甲地需42分，甲地到乙地全程是多少？
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