Pakistani and American joke

An American came in Pakistan and saw a newly constructed building
he asked a Pakistani engineer
American: in how many time this building was constructed.?
Pakistani: in one month "our engineers can build with in 2 weeks" replied the American

and saw another building and asked the same question
Pakistani: in two weeks
American: oops we can build within 2 days....
in another street American saw an old building and asked same question

Pakistani: Sorry i don't know "half an hour ago there was nothing"