In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip
was reduced by 200 km/hr and the time of flight increased by 30 minutes. What is the duration of the
flight ?
Choose one:	A) 3 hours	B) 2.4 hours	C) 1.4 hours	D) 1 hour	E) none of these

Rationale: "explanation : let the duration of the flight be x hours . then 600 / x − 600 / x + 1 / 2 = 200 600 / x − 1200 / 2 x + 1 = 200 x ( 2 x + 1 ) = 3 2 x 2 + x − 3 = 0 = > ( 2 x + 3 ) ( x − 1 ) = 0 neglecting the negative value for x we get x = 1 option d"
Answer: D