Tint percentage equations

[brand tints]

Hi. I literally haven't been on this forum for about 7 years. 

Anyway i have a question which I hope someone can answer. 

It's all to do with tint on top of tint percentages. 

My old boss could work it out easy but math's was never my strong point so i didn't understand it fully. 

For example : you have a window which has 20% window film on and the customer wants it darker... Therefore you put another 20% VLT on top of the existing 20% - so what percentage is it now???? 

The answer apparently is 4%.

I know this simply because i remember my old boss telling me so. 

So if you put a 35% on top of another 35% (without using a light metre and without removing the old film) what percentage is it now???? 

 

[Bham]

The formula is as follows  (VLT#1 X VLT#2) X 100 = %%   So 35% on top of 35% would yield 12.25% VLT  or  (.35 X .35 ) X 100 = 12.25 

[brand tints]

That's brilliant. So much easier than when it was explained to me years ago. (which i never understood back then) 

Thanks for your help. 

[jh812]

3 hours ago, Bham said:

The formula is as follows  (VLT#1 X VLT#2) X 100 = %%   So 35% on top of 35% would yield 12.25% VLT  or  (.35 X .35 ) X 100 = 12.25 

To lessen one of the steps just do the first number without the decimal. So 35x.35