Why does a change in income cause a parallel shift in the budget constraint

Clooney corp. establishes a petty cash fund for $225 and issues a credit card to its office manager. by the end of the month, employees made one expenditure from the petty cash fund (entertainment, $20) and three expenditures with the credit card (postage, $59; delivery, $84; supplies expense, $49).record all employee expenditures, and record the entry to replenish the petty cash fund. the credit card balance will be paid later. (if no entry is required for a transaction/event, select "no journal entry required" in the first account record expenditures from credit card and the petty cash fund.