The answer is 35 because if he has three shelves and 40 can fit on each, that would be 40 on shelf 1, 40 on shelf two and 5 on shelf three. 40 - 5 is 35. Therefore, it is 35.
He has room for 120 videos, so if he already has 85 videos the answer would be 120-85=35. The answer is 35 videos. You can double check your answer by adding 35 + 85 which equals 120.
