Question 96

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)?

Solution

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.

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