Let's say I have in cell A1 a combo box with options:
1. Expense
2. Refund
3. Tax
In cell B1 I will type a number
In cell C3 I want a formula like this:
If in cell A1 I have selected 1. Expense than calculate B1*25
If in cell A1 I have selected 2. Refund than calculate B1*50
If in cell A1 I have selected 3. Tax than calculate B1*150

How can I apply the combo box to entire column, like if I go to row 2 to
find in B1 the combo box from A1 and in C2 the formula from C1
Thanks for the help