PLEASE HELP KIND OF URGENT AND IM FAILING

1. In each case, which average do you think is most useful: the mean, median, or mode?
Justify your answer. (6 marks)
I
a) A storeowner wants to know which sweater sizes she should order. Last week she sold 5
small, 15 medium, 6 large, and 2 X-large sweaters.
b) Five of Robbie's friends said their weekly allowances are: $10, $13, $15, $11, and $10.
Robbie wants to convince his parents to increase his allowance.
c) Tina wants to know if her math mark was in the top half or bottom half of the class.