Buses A and B start from a common bus stop X. Bus A begins to travel in a straight line away from bus B at a constant rate of 60 miles per hour. One hour later, bus B begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour. If both buses travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes bus B to cover the exact distance that bus A has covered and the amount of time it takes bus B to cover twice the distance that bus A has covered?	Options
A) 36	B) 72	C) 132	D) 144	E) 180
1st part: - In 1hr, Bus A covers 30 miles.   Relative speed of bus ABus B is   (80-30)= 
<gadget id="calculator">  (80-30)</gadget>
<output>50</output>
50mph.   So time required for Bus B to cover the exact distance as A is   50*t= 30   t=3/5 = 36min   2nd part   80*t=2d - B has to cover twice the distance   30*(t+1) = d - A traveled 1hr more and has to travel only only d   so   d/30 - 2d/80 = 1   D=120   T= 3hrs = 180 min   Question asks for +ve difference between part 1 and part 2 in minutes   = 180-36 = 180min   180
<result>E</result>
Buses A and B start from a common bus stop X. Bus A begins to travel in a straight line away from bus B at a constant rate of 60 miles per hour. One hour later, bus B begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour. If both buses travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes bus B to cover the exact distance that bus A has covered and the amount of time it takes bus B to cover twice the distance that bus A has covered?