The Everything Bagel Theory Of Fare Collection . . .

. . . take all the crap-ass burnt bits and cobble together a fare:

On its first business day, the MTA’s fare hike yesterday baffled mass-transit travelers — who had conniptions over the higher costs — as discounts dropped from 20 percent to 15 percent on MetroCards.

“I was kind of confused. I didn’t read the question right,” said Alana Chitty, 21, who mistakenly bought a $20 card from a Grand Central Terminal vending machine when she only wanted a $7 card.

“I put $20 and got no change back,” she said. “I’m pissed. I want my money.”

The clerk at the nearby booth would not refund her money.

So Chitty, from Rye, was stuck with a $20 card that will leave her with a $3 bonus credit on the card. If she refills it for another $20, then she will have three “free” rides.

Had she got the $7 card she sought, she would have four rides because it comes with a $1.05 bonus — enough to pay for the fourth ride with a useless 5 cents left over.

She wasn’t the only one ticked off by the new transit tabulations.

“I was very annoyed that I didn’t get an extra round trip with my $10 card. Now I [have] $11.50 and I’m sure bits of money will be left on the card I won’t use,” said David Buckley, 48, an executive recruiter from Maplewood, NJ, at the Rockefeller Center station.

Another rider, Garian Giscombe, 25, felt the same about the $10 cards that used to provide one free ride.

“I don’t know what I’m gonna do with the $1.50 bonus,” he said.

But at least the cost of a single ride hasn’t gone beyond that of a slice of pizza, the usual indicator . . . after all, it’s important to keep up appearances.