tbentley.com

(Source)

Formula :
Price Elasticity (PED or Ed) = Change in Quantity / Change in Price

Where,
Change in Quantity = ((New Quantity – Original Quantity) / Original Quantity)
Change in Price = ((New Price – Original Price) / Original Price)

Here’s Patrick Burke writing in WaPo:

I also always speak alongside a LGBT athlete,

Good for him, talking about homophobia to sportsters.  But it should be “an LGBT athlete,” since the acronym is never spelled out in speech.

That’s why I prefer the acronym to be re-ordered as “GBLT”:  because it’s also a tasty sandwich.