Flight A usually takes 1 hour more than Flight B to travel a distance of 7200 km. Due to engine trouble speed of flight B falls by a factor of $$\frac{1}{6^{th}}$$, so it takes 36 minutes more than Flight A to complete the same journey? What is the speed of Flight A (in km/hr)?
Let say, B's speed is x km/h.
So, B takes(7200/x) hr .
So, A takes ((7200/x)+1) hr.
B's new speed is (5x/6) km/h .
So, B's new time=(7200×6)/5x hr .
So,
$$43200/5x=((7200/x)+1)+0.6$$
or,7200/5x=1.6
or, x=900.
A take (7200/900+1)=9 hr.
So,A's speed=7200/9=800 km/hr.
A is correct choice.
Create a FREE account and get:
