Answer: Yes, the rate went up by 2.73 dollars per hour.
The graph has slope 20 since each time x goes up by 1, y goes up by 20. The unit rate for the graph is 20 dollars an hour. You can use the slope formula to determine this as well.
If she charged $250 for 11 hours, then the unit rate is now 250/11 = 22.73 dollars an hour. She increased her hourly rate by 2.73 dollars.