Question 200842
Let {{{s}}} = the speed of the slower car
Let {{{s + 40}}} = the speed of the faster car.
The faster car will go further in the same time, so
{{{350 = (s + 40)*t}}} km
and
{{{150 = st}}}
{{{t = 150/s}}}
Substituting,
{{{350 = (s + 40)*(150/s)}}}
{{{350 = 150 + 6000/s}}}
{{{350s = 150s + 6000}}}
{{{200s = 6000}}}
{{{s = 30}}} km/hr answer