Question

'In' means 'no longer than a particular period of time' or 'at the end of a particular period of time.'

1. Can you finish the job in two weeks?
1-2. Can you finish the job in less than two weeks?
(Are both the same?)

2. I should be there in half an hour.
2-2. I should be there at the end of half an hour.
(Are both the same?)

3. I will leave for London ____ two days.
(If I may leave for London two days later, three days later, a week later, two weeks later, etc., what prepositions should we use in this blank?)

Answer 1

1 and 1-2 are almost the same.

2 and 2-2 are the same.

In 3, I'd use "in."