<PRE><B>Question 347982</B>
D=RT
D=400T FOR THE FIRST PLANE TO LEAVE.
D=500(T-1) FOR THE SECOND PLANE.
BECAUSE THE DISTANCES ARE THE SAME WE SET THESE 2 EQUATION EQUAL.
400T=500(T-1)
400T=500T-500
400T-500T=-500
-100T=-500
T=-500/-100
T=5 HOURS AFTER THE FIRST PALNE LEAVES THEY WILL MEET.
5-1=4 HOURS THE SECOND PLANE WILL BE IN THE AIR BEFORE OVERTAKING THE FIRST PLANE.
PROOF:
400*5=500(5-1)
2,000=500*4
2,000=2,000</PRE>