If one plane is flying at 40 mph while another is flying at 100 mph, and they are 200 miles apart and flying directly towards each other, how long will it take them to meet?

Time taken them to meet = 1.429 hours.

Explanation:

Speed of first plane = 40 mph

Speed of second plane = 100 mph

Distance between planes = 200 miles

If two objects with speed v and u are flying towards each other, their relative speed = v + u

So here relative speed = 40 + 100 = 140 mph

Time taken to meet = Distance/Speed = 200/140 = 1.429 hours.

Time taken them to meet = 1.429 hours.