Question 253133
Write 2 equations,1 for running
and 1 for walking
{{{d[r] = r[r]*t[r]}}}
and
{{{d[w] = r[w]*t[w]}}}
given:
{{{t[r] = 1/3}}} hr
{{{t[w] = 1/2}}} hr
{{{r[w] = 3}}} km/hr
{{{d[r] + d[w] = 4}}} km
-----------------
{{{d[r] = r[r]*t[r]}}}
{{{d[r] =r[r]*(1/3)}}} 
and
{{{4 - d[r] = 3*(1/2)}}}
{{{-d[r] = 3/2 - 4}}}
{{{-d[r] = -5/2}}}
{{{d[r] = 5/2}}}
and, since
{{{d[r] =r[r]*(1/3)}}}
{{{5/2 = r[r]*(1/3)}}}
{{{r[r] = 15/2}}}
He ran 7.5 km/hr
check:
{{{d[r] = r[r]*t[r]}}}
{{{5/2 = (15/2)*(1/3)}}}
{{{5/2 = 5/2}}}
OK