Multiply the price of the item by the percentage off, then subtract it from the price of the item. 
x= sale price
x= $150 - ($150 * 40%)
x= 150 - (150 * 0.40)
x= 150 - 60
x= $90 sale price
CHECK:
=150*60%
=$90
You can also find the sale price this way.  Multiply the original price by 100-sale percent). 
ANSWER: The sale price is $90.
Hope this helps!  :)