Question 661236
It is possible to tell from the problem who walks faster
Walking in the same direction, roberto over takes juanita.
If Roberto walked slower than her, he would never catch her
so he is the faster walker
Let {{{ r }}} = his speed in mi/hr
Let {{{ j }}} = her speed in mi/hr
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I can think of Juanita as standing still and Roberto as 
approaching at the difference of their speeds
(1) {{{ 5.5 = ( r - j )*11 }}}
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Walking toward each other, think of Juanita
as standing still and add their speeds
(2) {{{ 5.5 = ( r + j )*1 }}}
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(1) {{{ 5.5 = 11r - 11j }}}
and
(2) {{{ 5.5 = r + j }}}
(2) {{{ j = 5.5 - r }}}
substitute (2) into (1)
(1) {{{ 5.5 = 11r - 11*( 5.5 - r ) }}}
(1) {{{ 5.5 = 11r - 60.5 + 11r }}}
(1) {{{ 22r = 60.5 + 5.5 }}}
(1) {{{ 22r = 66 }}}
(1) {{{ r = 3 }}}
and, since
(2) {{{ j = 5.5 - r }}}
(2) {{{ j = 5.5 - 3 }}}
(2) {{{ j = 2.5 }}}
3 mi/hr is his speed in mi/hr
2.5 mi/hr is her speed in mi/hr
check:
In 11 hrs, she walks {{{ d = 2.5*11 }}}
{{{ d = 27.5 }}} mi
In 11 hrs, he walks {{{ d = 3*11 = 33 }}}
{{{ 33 - 27.5 = 5.5 }}}, so he makes up
the 5.5 mi difference
OK