Whenever, we need to convert a speed in km/hr to m/s, you multiply it by a factor of \(\frac{5}{18}\)
We arrive to \(\frac{5}{18}\) as follows :
1 km is 1000 meters
1 hr is 60 minute, and 1 minute is 60 seconds.
1 hr is 3600 seconds
So 1 km/hr essentially converts to \(\frac{1000}{3600}\) or \(\frac{5}{18}\)m/s
Therefore, In order to convert the speed from m/s to km/hr, you must multiply it by a factor of \(\frac{18}{5}\)Coming back to the question in hand
The car travels 2400 meters in 1 minute 48 seconds(108 seconds)
Speed(in m/s) = \(\frac{Distance}{Time} = \frac{2400}{108} = \frac{200}{9}\)
In order to convert the speed in the format that it has been asked in, we multiply it by a factor of \(\frac{18}{5}\)
So, the converted speed(in km/hour as asked in the question) is \(\frac{200}{9}*\frac{18}{5}\) =
80 km/hr.
Hi
Bunuel,
Can you please add options to this question to make it more GMAT-like!
Thanks
_________________
You've got what it takes, but it will take everything you've got
Connect with me on LinkedIn - https://www.linkedin.com/in/pushpit-chhajer-19388112a/