Question 736247
A man drives a car a distance of 200 km at an average speed of 44 km/h. What must be his average speed for the next 220 km if he is to cover the total distance in 9 hours?
<pre>
He wants to have gone the entire 420 miles in 9 hours. 

He has driven 200 km at 44 km/h.

Since {{{TIME=DISTANCE/RATE}}}, he has spent {{{200/44}}} or {{{50/11}}} or {{{4&6/11}}} hours.

So he has 220 miles to go, and he has 9-{{{4&6/11}}} or {{{49/11}}} or {{{4&5/11}}} hours left. So since {{{RATE=DISTANCE/TIME}}},

                  {{{220/(49/11)}}} = {{{220}}}×{{{expr(11/49)}}} = {{{2420/49}}} or {{{49&19/49}}} km/hr.

                  He must go {{{49&19/49}}} km/hr.

Edwin</pre>