Question 549986
The truck has a head start of
{{{ 45*(1/4) = 15 }}} mi 
Start a stopwatch when the car leaves
Let {{{t}}} = time on stopwatch when car catches truck
Let {{{d}}} = distance car travels until it catches truck
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Truck's equation:
{{{ d - 15 = 45t }}}
Car's equation:
{{{ d = 60t }}}
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By substitution:
{{{ 60t - 15 = 45t }}}
{{{ 15t = 15 }}}
{{{ t = 1 }}}
It will take the car 1 hour to catch the truck
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check:
{{{ d - 15 = 45*1 }}}
{{{ d = 60 }}}
and
{{{ d = 60*1 }}}
{{{ d = 60 }}}
OK