Question 716813
He has a head start of 
{{{ d[1] = 65* 3 }}}
{{{ d[1] = 195 }}} mi
start a stopwatch when the wife leaves
Let {{{ t }}} = time on stopwatch when they meet
Let {{{ d }}} = distance the wife has to travel
until she overtakes him
His equation:
(1) {{{ d - 195 = 65t }}}
Her equation:
(2) {{{ d = 90t }}}
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Substitute (2) into (1)
(1) {{{ 90t - 195 = 65t }}}
(1) {{{ 25t = 195 }}}
(1) {{{ t = 7.8 }}}
{{{ .8 }}} hrs = {{{ .8*60 = 48 }}} min
She will overtake him in 7 hrs 48 min
check:
(2) {{{ d = 90*7.8 }}}
(2) {{{ d = 702 }}} mi
and
(1) {{{ d - 195 = 65*7.8 }}}
(1) {{{ d = 507 + 195 }}}
(1) {{{ d = 702 }}} mi
OK