How to write a formula in Google spreadsheets to calculate a different percentage depending on the amount?

Question

Spreadsheets

It is necessary that, depending on the number in cell A1, I could calculate % in cell B1 (But it changes on a scale depending on the number A1):
6% if <=250
7% if <=300
8% if <=350
9% if <=400
what should the formula look like?

Answer 1

=ARRAYFORMULA(VLOOKUP(B10:B13;E2:F6;2;1))
Example https://docs.google.com/spreadsheets/d/1ehTUd_dP_A...