less than; Set A
It is less than, because if you add half of the sum of the least and greatest numbers of the set to the lowest number in the set, you get the median. The median of Set A was 17, and the Median of Set B was 17.5.
Set A is more variable in terms of range, because it has a larger range.
The answer should be 30. I hope this helps :)
Answer
Find out the conversion factor for seconds to minutes and convert 135 seconds to minutes.
To prove
1 minute = 60 second
for seconds to minutes.

Therefore the conversion factor for seconds to minutes be

Now convert 135 seconds to minutes.

= 2.25 minutes
Hence proved