Math geeks: Pop quiz, can you help with this rent money problem?

Here’s a math problem I’m having trouble with: Four roomates: John, Jim, Jack and Jill are trying to pay rent, which includes some variables.

Jack and Jill are a couple, they pay 40% of the rent. They also pay $20 of the amount for a parking spot. Jim and John pay 30% of the total rent each. But Jim has a discount on the rent… he’s a student, which earns a 5% off the total rent. But he calculates the dollar amount of that discount, and takes that dollar amount off his portion of rent. The total rent is $1282.80.

Who pays what?

(PS: It’d be cool if you can show how you reached the answer)