Question 967014
{{{ d = r*t }}}
{{{ d[1] = 45*3 }}}
{{{ d[1] = 135 }}}
The distance he needs to drive must
be 135 mi
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In {{{ 1 }}} hr,  he drives
{{{ d[2] = 45*1 }}}
{{{ d[2] = 45 }}} mi
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The remaining distance he has to drive is:
{{{ d[3] = d[1] - d[2] }}}
{{{ d[3] = 135 - 45 }}}
{{{ d[3] = 90 }}}
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He planned to drive for {{{ 3 - 1 = 2 }}} more hrs
He wants to drive for {{{ 2 - .5 = 1.5 }}} hrs
{{{ d[3] = r*1.5 }}}
{{{ 90 = r*1.5 }}}
{{{ r = 90/1.5 }}}
{{{ r =  60 }}}
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He will need to drive {{{ 60 }}} mi/hr to
arrive 1/2 hr early