



 
Hi, I can help get you started. First I would draw a diagram. John starts at $M$ and walks toward Max at 30 km/h and in 3 hours is at $X.$ What is the distance from $M$ to $X?$ At this time Max starts walking at 40 km/h towards John. At what rate is the distance between them changing? How long will it take for them to meet? I hope this helps,  


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