Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks. Francesca flew home from vacation with a heavy bag. With the first airline she flew, Francesca had to pay $20 to check her bag, plus $16 for every kilogram that her bag was over the weight limit. The next flight was with another airline that had the same weight limit. Francesca had to pay $20 per kilogram that her bag was over the weight limit, in addition to the checked bag fee of $16. By coincidence, the fees ended up being the same with both airlines. How far over the weight limit was the bag? How large was each airline's fee?