Question 923361
Michael's head start is:
{{{ d[1] = 9*2 }}}
{{{ d[1] = 18 }}} mi
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Start a stopwatch when the tour
boat leaves the dock
Let {{{ t }}} = time  in hrs on stopwatch
when boats meet
Let {{{ d }}} = distance in mi from
dock to Isles of Shoals
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Michael's equation:
(1) {{{ d - 18 = 9t }}}
tour boat's equation:
(2) {{{ d = 18t }}}
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By substitution:
(1) {{{ 18t - 18 = 9t }}}
(1) {{{ 9t = 18 }}}
(1) {{{ t = 2 }}} hrs
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The boats will meet in 2 hrs
check:
(1) {{{ d - 18 = 9t }}}
(1) {{{ d - 18 = 9*2 }}}
(1) {{{ d = 36 }}}
and
(2) {{{ d = 18t }}}
(2) {{{ d = 18*2 }}} 
(2) {{{ d = 36 }}}
OK