Answer:
To get the new price of the car multiply the original price by the percent increase in decimal form +1. 11% in decimal form is 0.11 = 11/100. Add one to this and you get 1.11 = 1 + 0.11. So now multiply $49,800 * 1.11 = $55,278. If the problem had said they decreased the price by 11% you would use 1 - 0.11 = 0.89 because 89% is 11% less than 100%.
Hope that helps!