Question 791157
Slow speed, r
Fast speed, 2r

r*t=d


Total time was 5 hours, so t=d/r and the other time would be d/(2r).
?

The amount of time, x, is the same for both cars.


CAR1___________r____________x__________rx
CAR2___________2r___________x__________2rx
Total______________________ 5__________450



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SYSTEM OF EQUATIONS:
{{{x+x=5}}} and {{{rx+2rx=450}}}
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{{{2x=5}}} and {{{rx+2rx=450}}}
{{{x=5/2}}} and {{{x(r+2r)=450}}}
Substitution for x gives {{{(5/2)(3r)=450}}}
{{{15r/2=450}}}
{{{r=450(2/15)}}}
{{{highlight(r=60)}}} for the slow car
Fast car is {{{highlight(120)}}} mph