Calculate depending on a price range

Hi!
I have price ranges for some bussines:

if 1 to 4 rooms = 100 euros per room
if 5 to 8 rooms = 90 euros per room
if 9 to 12 rooms = 80 euros per room
if 13 rooms and more = 70 euros per room

In one cell, I put a number of rooms (ex. 6) which means it costs 90 euros per room, the second cell should give me the result of 6*90 which is 540 euros.

examples:
if |cell A1= 9| then |cell A2= 9*80= |
if |cell A1= 2| then |cell A2= 2*100= |
if |cell A1= 18| then |cell A2= 18*70= |
etc.

Is it possible to make a formula that counts on this principle?
Thanx in advance, and sorry for my lousy english.