Answer:
Step-by-step explanation:
It's asking how many hours are left after 75 is done. Well, we need to know how many it started with. We know it was 10 hours a day for 11 days, well how many hours is that?
If you need to you can just count it up. 1 day would be 10 hours, 2 days would be 20 hours and so on, that leaves us with 110 hours.
Now, if 75 are already passed, that leaves 110-75 = 35
Let me know if there was anything you didn't understand.