Question 950675
Let {{{ d }}} = the distance in miles Carlos drove
Let {{{ t }}} = time in hrs that Carlos drove
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Carlos's equation:
(1) {{{ d = 53t }}}
Maria's equation:
(2) {{{ 258 - d = 51*( 5-t ) }}}
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Substitute (1) into (2)
(2) {{{ 258 - 53t = 51*( 5-t ) }}}
(2) {{{ 258 - 53t = 255 - 51t }}}
(2) {{{ 2t = 3 }}}
(2) {{{ t = 3/2 }}}
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Maria drove {{{ 5-t }}} hrs
{{{ 5 - t = 5 - 3/2 }}}
{{{ 5 - t = 3.5 }}}
Maria drove 3.5 hrs
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check answer:
(1) {{{ d = 53t }}}
(1) {{{ d = 53*(3/2) }}}
(1) {{{ d = 79.5 }}} mi
and
(2) {{{ 258 - d = 51*( 5-t ) }}}
(2) {{{ 258 - 79.5 = 51*( 5-3/2 ) }}}
(2) {{{ 178.5 = 51*3.5 }}}
(2) {{{ 178.5 = 178.5 }}}
OK