[MATH] Multiplicative percentages (Black Belt + Black Belt = 19%, not 20%)

[Hexerin]

I've spent the last half an hour searching for it, but I think I'm not entering the right search keywords because I can't find it.

What is the actual formula for combining percentages in a multiplicative way?

Additive is easy, you just add them together (10%+10%=20%) but multiplicative is something I just can't figure out. I need that formula.

[😎Macula😎]

My head just hurt what the heck you asking about? Are you asking about equiping two black belts don't give 20% or something entire different thing?

[Hexerin]

Originally posted by Macula:

My head just hurt what the heck you asking about? Are you asking about equiping two black belts don't give 20% or something entire different thing?

If you didn't understand, you wouldn't have the answer anyways.

[😎Macula😎]

In that case I gonna lurk till I get an answer from someone else.

Black Belt + Black Belt = moar curiosity

[Njugen]

10% * 10% = 0.1 * 0.1 = 1/10 * 1/10 = 1/100 = 0.01 = 1%

as 100% = 1 and therefore 10% = 0.1 which is equal to 1/10. Multiplication between two fractions a/b * a/b = a^2/b^2.

Formula: x * 1% = x/100

EDIT: See talgaby/Gonfuren's posts below. Misread the first post.

[talgaby]

It's basic 3rd grade math: Black belt level 1 = 10% damage reduction.
2× black belts for 2×10% reduction = (1-0.1)×(1-0.1) = 0.9×0.9 = 0.81, which is 19% damage reduction.

[Gongfuren]

10% resistance means you take 90% of the damage (a multiplier of 0.9 on the damage you take). Having two means 0.9 * 0.9 = 0.81 multiplier, so you would take 81% of the damage. Now, to convert from damage taken back to resistance, subtract like this: 100% - 81% = 19%.

[😎Macula😎]

Guess you gonna love when you able to upgrade black belt to level 5 it gives alone 20% resistence then

[Hexerin]

Originally posted by Gongfuren:

10% resistance means you take 90% of the damage (a multiplier of 0.9 on the damage you take). Having two means 0.9 * 0.9 = 0.81 multiplier, so you would take 81% of the damage. Now, to convert from damage taken back to resistance, subtract like this: 100% - 81% = 19%.

This one makes sense to me.

Thanks for the help everyone.