how can I set a formula in a box depending a word with conditional formating?

I would like to set a conditional formula with a formula in different boxes depending a word...

So I basically have such a spreadsheet :

value	factor	task_01	task_02	task_03
1500	facteur_01
4500	facteur_02
3000	facteur_01
200	facteur_03

depending the word in the column factor, I would like to set a formula like this :

if word in the column B is 'facteur_01'

set the formula =20%*A/75 in column C

set the formula =40%*A/75 in column D

set the formula =40%*A/75 in column E

if word in the column B is 'facteur_02'

set the formula =10%*A/75 in column C

set the formula =10%*A/75 in column D

set the formula =80%*A/75 in column E

I have think about doing it with script, but I guess conditional formatting will be more efficient. Thanks for the help

Solution

Conditional Formatting is meant to change the format of the cell (its cell background, color, bold or italic, for example); to change values you should use IF statements. For example, in C2:

=IF(B2="facteur_01",A2*0.20/75,IF(B2="facteur_02",A2*0.10/75,""))

You can use the same process to populate the rest of the values in row 2, and copy and paste down (or drag) ;)

Option 2, with different locale. Maybe you need semicolons instead of commas:

=IF(B2="facteur_01";A2*0.20/75;IF(B2="facteur_02";A2*0.10/75;""))