Question 1142664
Let {{{ s }}} = her walking speed
{{{ 12s }}} = her running speed
Let {{{ t }}} = her time spent walking
{{{ 7 - t }}} = her time spent running
-----------------------------------------
(1) {{{ 30 = s*t }}}
(2) {{{ 1 = 12s*( 7 - t ) }}}
------------------------------
(1) {{{ t = 30/s }}}
(2) {{{ 1 = 12s*( 7 - 30/s ) }}}
(2) {{{ 1 = 84s - 360 }}}
(2) {{{ 84s = 361 }}}
(2) {{{ s = 4.298 }}} mi/hr
and
{{{ 12s = 51.57 }}} mi/hr
------------------------------
check:
(1) {{{ t = 30/s }}}
(1) {{{ t = 30/4.298 }}}
(1) {{{ t = 6.981 }}} hrs
and
(2) {{{ 1 = 12s*( 7 - t ) }}}
(2) {{{ 1 = 12*4.298*.019 }}}
(2) {{{ 1 = .9799 }}}
close enough -check the math