



 
Hi Dee. Velocity (speed) is distance divided by time. We often writen this as:
We can solve this for d:
So if we use the subscripts _{C} and _{W} to refer to the cart and walk parts and the subscript _{T} to refer to the total, then we can write it this way:
Now since the total distance and time are just the sums of the two parts of the trip, we can replace d_{T} and t_{T} as shown below:
Next we use equation (2) to replace d_{C} and d_{W}:
It may look rather complicated, but you know all the values for these variables except t_{W}. Solve for t_{W} which is the time the man walks, substitute the values you know and you will answer your question. Hope this helps,  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 