Question 802138
the sum of the distances traveled by both planes is same = 2000

If first plane travels x miles then second plane travels 2000-x miles

First plane speed = 375 mph

second plane speed = 440 mph

First plane travels 375 * 1/4 = 93.75 miles before plane II starts


=2000-93.75=1906.25 miles they travel in same time

combined speed = 440 =375 = 815 mph

time taken = 1906.25/815 = 2.34 hours

add 0.25 hours of first plane

2.34+0.25 = 2.59 hours 

In 2.59 hours they will be 2000 miles away