Question 849732
Let {{{ t }}} = time for the 1st half of the trip
{{{ 40/60 - t }}} = time for the 2nd half of the trip
(1) {{{ d/2 = 100t }}}
(2) {{{ d/2 = 60*( 40/60 - t ) }}}
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(1) {{{ d = 200t }}}
(2) {{{ d/2 = 40 - 60t }}}
(2) {{{ d = 80 - 120t }}}
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Substitute (1) into (2)
(2) {{{ 200t = 80 - 120t }}}
(2) {{{ 320t = 80 }}}
(2) {{{ t = 1/4 }}}
and
(1) {{{ d = 200t }}}
(1) {{{ d = 200*(1/4) }}}
(1) {{{ d = 50 }}}
The distance traveled is 50 km
check:
(2) {{{ 50/2 = 60*( 40/60 - 1/4 ) }}}
(2) {{{ 25 = 40 - 15 }}}
(2) {{{ 25 = 25 }}}
OK