Question

The maximum speed of the Tupolev Tu -144 airliner is 694 m/s. What is this speed in kilometers per hour?

Answer 1

Answer: the correct answer would be 2498.4 km/h

*i got this question correct*

Answer 2

The answer is 2498.4km/h

The speed is $694m/s = \frac{694m}{1s}$

1 m = 0.001 km          ⇒        694 m = 694 * 0.001 km = 0.694 km
1 h = 60 min = 60 * 60 s = 3600 s 

Therefore:
$\frac{694m}{1s}= \frac{3600*0.694km}{3600s} = \frac{2498.4km}{1h} =2498.4km/h$