Question 640276
Tina's head start is {{{ 4*.5 = 2 }}} mi
Start a stopwatch when David leaves
They will both travel for the same amount
of time = {{{t}}} in hours
Let {{{ d }}} = distance David travels in miles 
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Tina's equation:
(1) {{{ d - 2 = 4t }}}
David's equation:
(2) {{{ d = 13t }}}
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Substitute (2) into (1)
(1) {{{ 13t - 2 = 4t }}}
(1) {{{ 9t = 2 }}}
(1) {{{ t = 2/9 }}}
Convert to minutes and seconds
{{{ (2/9)*60 = 40/3 }}}
{{{ 40/3 = 13 + 1/3 }}}
{{{ (1/3)*60 = 20 }}}
David catches up in 13 min 20 sec
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(2) {{{ d = 13*(2/9) }}}
(2) {{{ d = 26/9 }}}
(2) {{{ d = 2.889 }}}
{{{ d - 2 = .889 }}}
David travels 2.889 mi
Tina also travels 2.889 mi in {{{ 30 + 13 }}} min and {{{ 20 }}} sec
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check:
(1) {{{ d - 2 = 4t }}}
(1) {{{ 26/9 - 2 = 4*(2/9) }}}
(1) {{{ 26 - 18 = 8 }}}
(1) {{{ 26 = 26 }}}
OK