The passing standard is a scale score of 600; therefore, any score of 600 or higher is a passing score, and any score below 600 is a failing score. The number of questions that have to be answered correctly to achieve a score of 600 can change from form to form, but is generally within a 1-2 question range.
On all airlines, overweight baggage fees are normally even higher, ranging from $50 (Alaskan-Horizon Air) to $100-200 (United Airlines). Paying for checked luggage started in 2008 when American Airlines started charging a $15 fee for a first checked bag, and many airlines quickly followed suit.
On American, the $150 change fee would be deducted from the price of your original fare, and you would have a credit voucher of $350. Here's the other sad part about US Airways policies. Let's say you do pay your $200 change fee and your new ticket costs $200. Under this policy, you would lose the remaining $100. On American and Delta, if the new ticket costs $200, you get the rest after the change fee is deducted. Here's some more sad news: American Airlines and US Airways may merge, and the management team from US Airways will be operating the new American Airlines.