Question 347693
Let {{{s}}} = the speed of the other car.
Since they travel in opposite directions, 
I can consider Hillary's car to be stationary
and the other car to be traveling at the sum
of their speeds, which is {{{55 + s}}}
First the nose of the other car has to travel 15 ft
to get side-by-side, and another 15 ft to get
past Hillary's car.
{{{30*(1/5280) = (55 + s)*.2*(1/3600)}}} (there are 3600 sec /hour and 5280 ft/mile)
{{{.00568 = (55 + s)*.00005}}}
{{{.00568 = .00355 + .00005s}}}
{{{.00005s = .00213}}}
{{{s = 42.6}}}
The other car's speed is 42.6 mi/hr