Please answer this this question is a motion problem:
 

   A pilot plans to make a flight lasting 2 hours and 30 minutes. How far can he fly from the airport at the rate of 600 mph and return over the same route at the rate of 400 mph?



Answer :

t1 + t2 = 2h and 30min;
t1 * 600 = t2 * 400 => t2 = (3/2) * t1;

then, t1 +  (3/2) * t1 = 2h and 30min => 2t1 + 3t1 = 5h => 5*t1 = 5h => t1 = 1h => t2 = 1h and 30 min;

The distance is 2 * 1 * 600 = 1200miles;