for the first one he has 3100 that comes out of his monthly payment so look for the one that has 3100 or more on his paycheck and that will be the month that he has enough to pay his monthly expencize. I hope that is right im pretty sure it is.
I wish I could help you with the second one but the way I would explain it is to confusing but I hope you find help on that one! have a good day
