Calculation formula greater than less than

[AaruJaan]

Hi Experts,
I'm looking formula in D column to calculate according the criteria, Example:

In this example I need Cell D2 to be:
-up to the first 40 hours is $10.00 per hour in this example-anything over 40 hours (7 in this example) is paid 1.5 times the hourly pay of $10
-So the total for cell D2 needs to be: (40*10)+(7*15)=505


I want the same formula for cell D2 that will work in D3 as well where there is no amount over 40 hours. So D3 will be (36*11)+(0*16.5)=396

Thanks in Advance.
gul