Can someone me with questions number 1 and 2?

What is the interquartile range of this data set? 2, 5, 9, 11, 18, 30, 42, 48, 55, 73, 81

What is the inverse of f(x) = 6x -24

Tatiana reads 40 pages of her book every night for x number of nights. write an expression that shows the number of pages she has read