A helicopter covers a distance in 4 hours at 280 km/h. To complete the same journey in 50 minutes, what speed is needed?

The correct answer is 1344 km/h.

Step 1: Calculate the total distance of the journey.
We are given that the helicopter travels for 4 hours at a speed of 280 km/h.
Using the distance formula:

$\text{Distance}=\text{Speed}\times \text{Time}$

$\text{Distance}=280 \text{km/h}\times 4 \text{hours}=1120 \text{km}$

Step 2: Convert the new required time into hours.
The new target time to cover the same distance is 50 minutes.
Since speed is measured in km/h, we convert minutes into hours by dividing by 60:

$\text{Time in hours}=\frac{50}{60}=\frac{5}{6} \text{hours}$

Step 3: Calculate the required speed.
Using the speed formula:

$\text{Required Speed}=\frac{\text{Distance}}{\text{Time}}$

$\text{Required Speed}=\frac{1120}{5/6}=1120\times \frac{6}{5}$

$\text{Required Speed}=224\times 6=1344 \text{km/h}$

Thus, the speed needed to cover the distance in 50 minutes is 1344 km/h.