Which of the following speeds is equal to 30 m/s when converted to km/h?

To convert a speed from meters per second (m/s) to kilometers per hour (km/h), you would use the conversion factor where 1 m/s is equivalent to 3.6 km/h. So, to find the equivalent speed in km/h of 30 m/s, you multiply 30 by 3.6:

( 30 , \text{m/s} \times 3.6 , \frac{\text{km/h}}{\text{m/s}} = 108 , \text{km/h} )

This calculation shows that the correct conversion of 30 m/s yields 108 km/h, confirming that this is the right answer. The other options (72 km/h, 60 km/h, and 90 km/h) result from dividing the speed by the conversion factor or using incorrect multiplication factors, which do not accurately represent the speed of 30 m/s converted into kilometers per hour.