Hello friends,
Since I'm mathematically challenged, I'm coming to you for wise assistance please.

I'd like the simplest formula to calculate:

The number that is 5% lower than the mean difference between 521 and 571

*THE RESULT of the formula will be 518.7 (or 519). << (((571-521)/2)+521)*.95 >>

I'm thinking there must be a simpler way to arrive at that number. This little formula will be used in a more massive IF/THEN/ELSE formula, so the shorter this is the better.

Thanks in advance!