Question 188929
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Car[1] = Speed[1] = 32mi/hr
Car[2] = Speed[2] = 47mi/hr


Remember for Speed  = Distance / time


And Distance = Speed*time (working Eqn)


We both cars will be apart by 69 miles in <font color=blue> t (hours)


So we need to subtract their speed in relevance to the time when they're apart 69 miles</font>.


Putting into equation:
{{{69mi=S[2]*t - S[1]*t}}}
{{{69= 47t - 32t}}}
{{{69=15t}}} -----> {{{cross(69)4.6/cross(15)=cross(15)t/cross(15)}}}
<font color=blue>t=4.6 hours</font> or <font color=blue>4 hours and 36 minutes</font>


Let's check:
{{{D[1]=S[1]*t=32*4.6=red(147.2miles)}}}
{{{D[2]=S[2]*t=47*4.6=red(216.2miles)}}}


Difference: {{{D[2]-D[1]=216.2-147.2 = highlight(69miles)}}}


Thank you,
Jojo</font>