Question 793578
Lysa's head start is 
{{{ d[1] = 10*1.5 }}}
{{{ d[1] = 15 }}}
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Start a stop watch when Morton leaves
 {{{ .5 }}} = time in hrs on stopwatch when
he catches Lysa
Let {{{ d }}} = distance Morton travels in time {{{ t }}}
Let {{{ r }}} = Morton's rate in mi/hr
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Morton's equation:
(1) {{{ d = r*(.5) }}}
Lysa's equation:
(2) {{{ d - 15 = 10*(.5) }}}
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(2) {{{ d = 5 + 15 }}}
(2) {{{ d = 20 }}}
and
(1) {{{ 20 = .5r }}}
(1) {{{ r = 20/.5 }}}
(1) {{{ r = 40 }}}
His rate was 40 mi/hr