At 10a.m. Juan leaves the city traveling north at 60 mi/hr. One hour later mel leaves the city traveling south at 50 mi/hr. At what time will they be 830 miles apart?
\(\frac{60}{1} = \frac{830}{x}\)
\(60x = 830\)
\(x = 13.83\)
\(10 + 13.83 = 23.83\)
23.83 hours is around 11:50pm
\(\frac{50}{1} = \frac{830}{x}\)
\(50x = 830\)
\(x = 16.6\)
\(11 + 16.6 = 27.6\)
\(27.6 - 24 = 3.6\)
3.6 is around 1:36am
-- At 11 AM, when Mel starts out, Juan has already covered 60 miles.
-- After that, since they're traveling in opposite directions, the distance
between them increases (60 + 50) = 110 miles every hour.
Let's call 'H' the number of hours after 11 AM.
Then the distance between them is
D = 110H + 60
When is this distance 830 miles ? Wouldn't you like to know !
830 = 110H + 60
Subtract 60 from each side:
770 = 110H
Divide each side by 110 :
H = 770 / 110 = 7 .
It happens 7 hours after 11 AM.
That would be 6:00 PM .