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. The duration of the flight is:
1 hour
2 hours
3 hours
4 hours
Explanation:
Let the duration of the flight be $ x $ hours.
| Then,$ \dfrac{600}{x} $-$ \dfrac{600}{x + (1/2)} $= 200 |
| $\Rightarrow \dfrac{600}{x} $-$ \dfrac{1200}{2x + 1} $= 200 |
$\Rightarrow x \left(2x + 1\right)$ = 3
$\Rightarrow$ 2$ x $2 + $ x $ - 3 = 0
$\Rightarrow$ $\left(2x + 3\right)\left(x- 1\right)$ = 0
$\Rightarrow x $ = 1 hr. [neglecting the -ve value of $ x $]