Is 40% alcohol 2.5% stronger or 6.666’% stronger than 37.5% alcohol?

Question

So I’ve always considered myself fairly competent at maths and this has absolutely stumped me.

Initially my brain says obviously 40% alcohol is 2.5% stronger than 37.5% alcohol, but 2.5 is 6.666’% of 37.5, so is 40% alcohol actually 6.666’% stronger than 37.5% alcohol?

Someone help me I feel like I’m going mad

In: Mathematics

Answer 1

It’s 6.666% stronger because it’s in reference to the 37.5%. You could say a 40% alcohol is 2.5 percentage points higher in alcohol than a 37.5% because that is in reference to the whole volume

Edit: corrected due to my friend’s comment