1. He runs 50 meters in 9 seconds.

Question

2. He runs 50 meters durng 9 seconds.
[Can we use #2?]

3. He finished the project in 5 days.
4. He finished the project during 5 days.
5. He finished the proj\ect during the 5 days.
[Are they all the same? Which ones are correct?]

Answer 1

#2 is not used. #1 is the usual way to express this idea.

#3, 4, and 5 all mean about the same thing, but 4 and 5 are not normally used expressions.