Question

In a flight of $600$ km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by $300$ km/hr and the time of flight increased by $1$ hour. The duration of the flight is

• A. $1$ hour
• B. $2$ hours
• C. $3$ hours
• D. $4$ hours

Answer 1

The correct option is A $1$ hour

Let the duration of the flight be $x$ hours.
Then, $\frac{600}{x}-\frac{600}{x+1}=300$
$600x+600-600x=300$ $(x^2+x)$
$600=$ $300x^2+300x$
$300x^2+300x-600=0$
Divide $300$ on both the sides, we get,
$x^2+x-2=0$
$(x+2)(x-1)=0$
$x=1$ hour (neglecting the negative value of $x$)