Question 1128428
Let {{{ t }}} = time in hrs for for the roadster to
be 80 mi from horse & buggy
Let {{{ d }}} = distance in miles the roadster
travels in {{{ t }}} hrs
{{{ 10*2 = 20 }}} mi is the horse & buggy's head start
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Equation for Horse & buggy:
(1) {{{ 80 - d - 20 = 10t }}}
Equation for roadster:
(2) {{{ d = 30t }}}
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(1) {{{ 80 - 30t - 20 = 10t }}}
(1) {{{ 40t = 60 }}}
(1) {{{ t = 1.5 }}}
The roadster left at 2 pm
2 pm + 1.5 hrs = 3:30 pm
At 3:30 pm they are 80 mi apart
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check:
(1) {{{ 80 - d - 20 = 10*1.5 }}}
(1) {{{ 60 - d = 15 }}}
(1) {{{ d = 45 }}} mi
and
(2) {{{ d = 30*1.5 }}}
(2) {{{ d = 45 }}} mi
OK