Question 426006
He walked the same distance that he drove
Call this distance {{{d}}}
Let {{{t}}} = time spent driving
given:
driving equation:
(1) {{{ d = 40t }}}
Walking equation:
(2) {{{d = 5*(2.25 - t) }}}
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From (2),
{{{ d = 11.25 - 5t }}}
By substitution:
{{{ 40t = 11.25 - 5t }}}
{{{ 45t = 11.25 }}}
{{{ t = .25 }}}
Plug this back into (1)
{{{ d = 40*.25 }}}
{{{ d = 10 }}}
He broke down 10 miles from his home
check:
(2) {{{d = 5*(2.25 - t) }}}
(2) {{{d = 5*(2.25 - .25) }}}
{{{ d = 10 }}}
OK