Question 697595
Let {{{ w }}} = his speed walking
Let {{{ d }}} = his speed driving
given:
(1) {{{ w*(20/60) + d*90/60 = 46 }}} miles
(2) {{{ w*(40/60) + d*( 70/60) = 37 }}} miles
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(1) {{{ 20w + 90d = 2760 }}}
(1) {{{ 2w + 9d = 276 }}}
and
(2) {{{ 40w + 70d = 2220 }}}
(2) {{{ 4w + 7d = 222 }}}
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Multiply both sides of (1) by {{{ 2 }}}
and subtract (2) from (1)
(1) {{{ 4w + 18d = 552 }}}
(2) {{{ -4w - 7d = -222 }}}
{{{ 11d = 330 }}}
{{{ d = 30 }}}
and, since
(1) {{{ 2w + 9d = 276 }}}
(1) {{{ 2w + 270 = 276 }}}
(1) {{{ 2w = 6 }}}
(1) {{{ w = 3 }}}
He walks 3 mi/hr and
drives 30 mi/hr