Question 615427
Let {{{ d }}} = the one-way distance from home to school
Let {{{ w }}} = his speed walking
Let {{{r }}} = his speed riding
Let {{{ t }}} = his time walking one-way
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Walking and riding:
{{{ d = w*t }}}
{{{ d = r*( 1.5 - t ) }}}
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Just riding:
{{{ 2d = r*.5 }}}
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It doesn't really matter what I say the distance is.
No units of speed or distance are given. I will say 
the distance is {{{ 1 }}} unit of length and the speeds
are units/hour.
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(1) {{{ 1 = w*t }}}
(2) {{{ 1 = r*( 1.5 - t ) }}}
(3) {{{ 2 = .5r }}}
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(2) {{{ 1 = 1.5r - r*t }}}
and
(3) {{{ r = 2/.5 }}}
(3) {{{ r = 4 }}} units/hr
and
(2) {{{ 1 = 1.5*4 - 4t }}}
(2) {{{ 4t = 6 - 1 }}}
(2) {{{ 4t = 5 }}}
(2) {{{ t = 1.25 }}} hrs
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(1) {{{ 1 = w*1.25 }}}
(1) {{{ w = .8 }}} units/hr
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{{{ 2*1 = w*(2t) }}}
{{{ 2t = 2/w }}}
{{{ 2t =  2/.8 }}}
{{{ 2t = 2.5 }}}
It will take him 2.5 hrs walking both ways
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check:
(2) {{{ 1 = 1.5r - r*t }}}
(2) {{{ 1 = 1.5*4 - 4*1.25 }}}
(2) {{{ 1 = 6 - 5 }}}
{{{ 1 = 1 }}}
OK