How can you add subtract multiply with decimals

What is the interquartile range (iqr) of the data set represented by this box plot?

Captain umaima has a ship, the h.m.s. khan. the ship is two furlongs from the dread pirate nadia and her merciless band of thieves. the captain has probability 3/7 of hitting the pirate ship. the pirate only has one good eye, so she hits the captain's ship with probability 2/5. if both fire their cannons at the same time, what is the probability that the captain hits the pirate ship, but the pirate misses.

Type the next three numbers in a sequence 80, 90, 85, 95, 90, 100, 95, 105