A. Average tsunamis per year = total number of tsunamis/# of years
= 17/5 = 3.4 tsunamis per year on average
B. Lives per year lost = total number of lives lost/ # of years
= 1700/5 = 340 lives lost per year
Note: whenever you see the word "per," it means divide. somethingA per somethingB means somethingA/somethingB
Other words to note: "sum" means add, "difference" means subtract, "of" or "product" means multiply.