Question 675768
Let {{{ d }}} = the one-way distance to store
Let {{{ t }}} = time going to store ( one-way time )
given:
(1) {{{ d = 8t }}}
(2) {{{ d = 4*( 2 - t ) }}}
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Substitute (1) into (2)
(2) {{{ 8t = 4*( 2 - t ) }}}
(2) {{{ 8t = 8 - 4t }}}
(2) {{{ 12t = 8 }}}
(2) {{{ t = 2/3 }}} ( 40 minutes )
and
(1) {{{ d = 8t }}}
(1) {{{ d = 8*(2/3) }}}
(1) {{{ d = 16/3 }}}
{{{ 2d = 32/3 }}}
{{{ 2d = 10.667 }}} miles round-trip
check answer:
(2) {{{ d = 4*( 2 - t ) }}}
(2) {{{ 16/3 = 4*( 2 - t ) }}}
(2) {{{ 16/3 = 8 - 4t }}}
(2) {{{ 4t = 24/3 - 16/3 }}}
(2) {{{ 4t = 8/3 }}}
(2) {{{ t = 2/3 }}}
OK