Calculation of charges based od tariff pricelist

Good day to all,

please give me solution for my tarrif calculation:

In have a tariff witch structure is:

B10 = charge from 1-5 pcs
C10 = 6-10
F10 = 11-20
G10 = 21-30
H10 = 30 ->

So if you enter in A2 for example 22 it should be = 5*B10+5*C10+10*F10+2*G10..

How shoul the formula look? ..i have no idea how to do it...

please help