[Closi]

> It really isn't.

The assertion was "$10/m they'll need 5x customers to reach same revenue"

Revenue = Price * Quantity Sold.

Let x = Quantity Sold, and y = revenue

$50 * x = y

$10 = $50/5

$50/5 * x = y/5

$10 * 5x = y

OP stated a fact, and you said it was incorrect. I'm just trying to say the disagreement is actually about how elastic the price is (i.e. a change of x% in price results in a y% change in the number of customers).