What is the interquartile range of the data set? 5,6,7,8,9,10,11

Asequence is a function whose is the set of natural numbers

The oates family went out for dinner the price of the meal was $33.95 the sales tax was 7.25% of the price of the meal . the tip was 15% of the meal and the sales tax . how much money did the oates family pay for the meal, including tax and tip

If a=0.333333 and b=0.55555, what is the value of a+b