We can’t subtract the minutes here because
10 minutes < 35 minutes.
So, we carry 1 hour from 4 hours to minutes side.
Now, 10 minutes + 60 minutes = 70 minutes
and 70 minutes – 35 minutes = 35 minutes.
In the hours we are left with
3hours – 1 hour = 2hours.
The answer is 2:35.