Question 699846
Let {{{ d }}} = the one-way distance he rowed in miles
Let {{{ t }}} = his time going upstream in hrs
given:
(1) {{{ d = 6t }}}
(2) {{{ d = 12*( 3 - t ) }}}
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Substitute (1) into (2)
(2) {{{ 6t = 12*( 3 - t ) }}}
(2) {{{ 6t = 36 - 12t }}}
(2) {{{ 18t = 36 }}}
(2) {{{ t = 2 }}}
{{{ 3 - t = 3 - 2 }}}
{{{ 3 - t = 1 }}}
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(1) {{{ d = 6t }}}
(1) {{{ d = 6*2 }}}
(1) {{{ d = 12 }}}
and
(2) {{{ d = 12*( 3 - t ) }}}
(2) {{{ d = 12*( 3 - 2 ) }}}
(2) {{{ d = 12*1 }}}
(2) {{{ d = 12 }}}
His distance for the trip was {{{ 2d }}} or 24 mi
What you did was right. You just had to
make the 2 distances equal to each other.