We'll go to the nearest hour, which is 7:00 pm
7:00 pm is 10minutes before the time she finished so we can subtract 10 minutes from the total time 35minutes-10minutes=25minutes
in an hour there is 60 minutes
so 60-25=35 minutes
And because we are subtracting to find the time she started we know she couldn't have started at or before 7:00pm
so...she started her research at 6:35pm