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

You can phrase it as an addition problem, or as a multiplication problem:

* 40% is 2.5 percentage points higher than 37.5% (.375 **plus**.025 = 0.4).

* 40% is 6.67% higher than 37.5% (.375 **times** 1.0667 = 0.4).

It’s correct both ways.