Question 328422
given:
Katy:
{{{d = r*t}}}
{{{40 = r[k]*t[k]}}}
Chad:
{{{90 = 3r[k]*(t[k] - 2)}}}
{{{90 = 3*r[k]*t[k] - 6r[k]}}}
By substitution:
{{{90 = 3*40 - 6r[k]}}}
{{{6r[k] = 120 - 90}}}
{{{6r[k] = 30}}}
{{{r[k] = 5}}} mi/hr
and
{{{r[c] = 3r[k]}}}
{{{r[c] = 15}}} mi/hr
How long did they travel?
{{{t[k] = 40/r[k]}}}
{{{t[k] = 40/5}}}
{{{t[k] = 8}}} hrs
and
{{{t[c] = 90/r[c]}}}
{{{t[c] = 90/15}}}
{{{t[c] = 6}}} hrs
Katy traveled for 8 hrs
Chad traveled for 6 hrs