Question 525597
The freight train has a head start of
{{{ d[1] = 60*(1/2) }}}
{{{ d[1] = 30 }}} mi
Start a stop watch when the passenger train leaves
They will both travel for the same amount of time
until they meet. Call this time {{{t}}}
Let {{{d}}} = distance passenger train goes
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For passenger train:
(1) {{{ d = 72t }}}
For freight train:
(2) {{{ d - 30 = 60t }}}
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Substitute (1) into (2)
(2) {{{ 72t - 30 = 60t }}}
(2) {{{ 12t = 30 }}}
(2) {{{ t = 2.5 }}}
It will take the passenger train
2.5 hrs to catch the freight train