Question 993957
Let {{{ d }}} = distance in miles she traveled by bus
{{{ 910 - d }}} = distance in miles she traveled by train
Let {{{ t }}} = time in hrs she spent on bus
{{{ 10.5 - t }}} = time in hrs she spent on train
-----------------------------------------
Equation for bus:
(1) {{{ d = 30t }}}
Equation for train:
(2) {{{ 910 - d = 115*( 10.5 - t ) }}}
-----------------------------
Substitute (1) into (2)
(2) {{{ 910 - 30t = 115*( 10.5 - t ) }}}
(2) {{{ 910 - 30t = 1207.5 - 115t }}}
(2) {{{ 85t = 297.5 }}}
(2) {{{ t = 3.5 }}}
and
{{{ 10.5 - t = 10.5 - 3.5 }}}
{{{ 10.5 - t = 7 }}}
Wendy spent 7 hrs on the train
--------------------------
check:
(1) {{{ d = 30t }}}
(1) {{{ d = 30*3.5 }}}
(1) {{{ d = 105 }}}
and
(2) {{{ 910 - d = 115*( 10.5 - t ) }}}
(2) {{{ 910 - d = 115*( 10.5 - 3.5 ) }}}
(2) {{{ 910 - d = 805 }}}
(2) {{{ d = 105 }}}
OK