Question 275106
Bill is pulling ahead of Leo at the rate of
{{{12 - 10 = 2}}} km/hr
The problem doesn't change if you think 
of Leo as being stationary and Bill moving
at {{{2}}} km/hr. Now how long does it take
Bill to get {{{2/3}}} km from Leo?
{{{t=d/r}}}
{{{t = (2/3)/2}}} hr
{{{t = 1/3}}} hr
In 20 min, they will be {{{2/3}}} km apart