Question 1146609
Let {{{ t }}} = time for the car to pass the truck
{{{ 60*( 9/60 ) = 9 }}} miles = the truck's head start in miles
{{{ d }}} = distance in miles the car travels until it passes truck
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Start a stop watch when the car leaves
equation for the car:
(1) {{{ d = 66t }}}
equation for the truck:
(2) {{{ d - 9 = 60t }}}
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Plug (1) into (2)
(2) {{{ 66t - 9 = 60t }}}
(2) {{{ 6t = 9 }}}
(2) {{{ t = 1.5 }}} 
The car takes 1.5 hrs to pass truck
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check:
(1) {{{ d = 66*1.5 }}}
(1) {{{ d = 99 }}} mi
and
(2) {{{ d - 9 = 60*1.5 }}}
(2) {{{ d - 9 = 90 }}}
(2) {{{ d = 99 }}} mi
OK