A student skipped a step when she tried to convert 15 hours to seconds, and she got the following incorrect result?

15 hours (60 seconds),/1 minute=900seconds

She did not convert 1 minute into 60 seconds. and 15 hours in seconds.

she did it like this:

15min * 60 seconds/1 min

900 seconds.

The SI unit of time is second so she should have converted the hours and minutes into seconds first and then start the calculation.

60mins/1 hour