If a man travels p hours at an average rate of q miles per hour, and then r hours at an average rate of s miles per hour, what is his overall average rate of speed?
Total miles traveled in p hours = p*q miles and Total miles traveled in r hours = r*s miles so, average rate of speed = total miles traveled / number of hours =[{(p*q)+(r*s)} / (p+r)] miles per hour
