Excel 2007 : Difficult Formula Question

I'm trying to create a conditional formula in Excel 2007 to calculate a dollar amount, based on a set of tiered numbers.
IF D2= any number 1 through 10, multiply it by 50
IF D2= any number between 11 through 14, multiply by 75
IF D2= any number greater than 15, multiply by 100

Here's what I have, but this isn't working - it keeps saying TRUE when I enter in numbers into D2.

=IF(D2<11,D2*50)=AND(D2>10,D2<15,D2*75)=AND(D2>14,D2*100)

Any help would be appreciated!

Thanks!
Lauren

That worked perfect DaddyLongLegs!
Thank you !!!!!!!!!!!!!!