Mental Math: Bhajan Buys Bricks

Bhajan  went  to  buy  bricks.The  price  was  given  one
thousand  bricks.  The  prices  were  also different  for
different types of bricks.

old bricks     - Rs 1200 for one thousand bricks
New bricks from Intapur     - Rs 1800 for one thousand bricks
New bricks from Brikabad    - Rs 2000 for one thousand bricks

Bhajan decided to buy the new bricks from Brickabad.
Heo bought three thousand bricks. How much did he pay ?

[toggle title="Answer" float="left" width="100px" margin="0 20px 20px 0" status="closed"]Rs 6000[/toggle]

Guess what he will pay if he buys 500 old bricks ?
Do this without writing.

[toggle title="Answer" float="left" width="100px" margin="0 20px 20px 0" status="closed"]Rs 600[/toggle]