Question 118233
There are are 2 parts of the trip. I'll call them {{{a}}} and {{{b}}}
For part{{{a}}},
speed  = {{{s[a] = s}}}km/hr
time = {{{2}}}hours
distance = {{{d[a] = d}}}km
For part{{{b}}}.
speed = {{{s[b] = s-7}}}
time = {{{2}}}hours
distance = {{{d[b] = 206 - d}}} km
{{{d[a]/s[a] = d[b] / s[b]}}}
{{{d / s = (206 - d) / (s - 7)}}}
Also, I know that {{{d / s = 2}}}
{{{d = 2s}}}
{{{d / s = (206 - d) / (s - 7)}}}
{{{2s / s = (206 - 2s) / (s - 7)}}}
{{{2(s - 7) = 206 - 2s}}}
{{{2s - 14 = 206 - 2s}}}
{{{4s = 220}}}
{{{s = 55}}} km/hr answer
check answer
{{{d = 2s}}}
{{{d = 110}}}km
{{{d / s = (206 - d) / (s - 7)}}}
{{{110 / 55 = (206 - 110) / 48}}}
{{{2 = 96 / 48}}}
{{{2 = 2}}}
OK