Problema Solution
Two planes leave an airport at 1:00 pm and flying in opposite directions. The plane going east flies at 300 mph and the one going west has a speed of 400 mph. How long does it take for them to be 850 miles apart? According to the clock, what time will that be?
Answer provided by our tutors
Let the planes be 850 miles apart after t hours from the start
Distance covered by plane bound east in t hours = speed x time = 300 t
Distance covered by plane bound west in t hours = speed x time = 400 t
Distance between them = 300t + 400t = 700t
But the distnace is 850 miles
700 t = 850
t = 850/700 = 1.20 hrs apx
Hence the planes will be 850 miles apart after 1.20 hrs of flight and at 2:20 pm