Question 670787
Let {{{ d }}} = distance that Vera walked
Let {{{ t }}} = time Vera spent walking
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given:
Walking:
(1) {{{ d = 3t }}}
Driving:
(2) {{{ 16 - d = 30*(  50/60 - t ) }}}
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(2) {{{ 16 - d = 25 - 30t }}}
(2) {{{ d = 30t - 9 }}}
Substitute (1) into (2)
(2) {{{ 3t = 30t - 9 }}}
(2) {{{ 27t = 9 }}}
(2) {{{ t = 1/3 }}}
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(1) {{{ d = 3*(1/3) }}}
(1) {{{ d = 1 }}}
{{{ 16 - d = 16 - 1 }}}
{{{ 16 - d = 15 }}}
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She walked 1 mi and drove 15 mi
check:
(2) {{{ 16 - d = 30*(  50/60 - t ) }}}
(2) {{{ 16 - 1 = 30*(  5/6 - 1/3 ) }}}
(2) {{{ 15 = 30*( 5/6 - 2/6 )  }}}
(2) {{{ 15 = 30*(1/2) }}}
(2) {{{ 15 = 15 }}}
OK