A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.
How long he can cover the distance of one side at a still lake with no current?
I am a word that begins with the letter “i.†If you add the letter “a†to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?