Formula help please - Min & Max outcome

[Zohanigan]

Hi,

I need a formula that will return a number based on the following:

anything over 160 but less than 300 multiplied by 7.5% (so if I have 250 the answer would be (250-160)*7.5% = 6.75) and 350 would give 10.5 (140*7.5%) where 140 is the difference between the max and min figures

I was trying to do it with an if sum but can't make it work :-(