A plane takes off from an airport and flies east at a speed of 350 mph. Ten minutes later, a second plane takes off from the same airport and flies east at a higher altitude at a speed of 400 mph. How long does it take the the second plane to overtake the first plane?

Answer 1

if t=0 when the second plane leaves, then you want t when

350(t + 1/6) = 400t
t = 7/6 or 1:10 hours

Or, consider that in 10 minutes, the 1st plane flies 58.333 miles. The 2nd plane, going 50 mph faster, then must take 58.333/50 = 7/6 hours to make up the difference