Why do gas stations charge 9/10ths of a cent, and how do they even take that out of your bank account?

Question

Why do gas stations charge 9/10ths of a cent, and how do they even take that out of your bank account?

In: Other

Answer 1

Because if you have one gas station charging you 1.90^^9 and another charging you 1.91, the first one will look one cent cheaper while still making 90% of that cent.

And in the end, they round the result. You’re already multiplying the price with a a fractional number of units (liters/gallons). If you buy 5.1 gallons at 1.91, that’s just as inconvenient (9.741) as exactly 5 gallons at 1.909 (9.545).