Question 349632
For Allison:
{{{d = r*t}}}
{{{d = 50t}}}
For Rachel:
{{{480 - d = 40*(t - 3/4)}}}
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By substitution:
{{{480 - 50t = 40t - 30}}}
{{{90t = 510}}}
{{{t = 5.667}}}
{{{d = 50t}}}
{{{d = 283.333}}}
Rachel drove:
{{{480 - 283.333 = 196.667}}} mi
check answer:
{{{480 - d = 40*(t - 3/4)}}}
{{{480 - 283.333 = 40*(5.667 - .75)}}}
{{{196.667 = 40*4.9167}}}
{{{196.667 = 196.667}}}