Question 107492
10 minutes is {{{1/6 }}}hour, so in the first 10 minutes, the robbers will have traveled {{{70/6}}}miles, or {{{11.67...}}}miles.  Since the police are travelling 8 mph faster than the robbers, the question becomes how long will it take to travel 11 and 2-thirds miles at 8 mph.


{{{t=d/r}}}
{{{t=11.67/8}}}

{{{t=1.46}}} hour.


To check, realize that the robbers have been travelling for 10 minutes (0.167 hour) longer than the police, so the robbers have been travelling 1.46 + 0.167 = 1.63 hours


{{{d=78*1.46=113.75}}}
{{{d=70*1.63=113.75}}}.  They are the same, so 'You are under arrest, you have the right...'