PLEASE I NED HELP.

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Ameteorologist is studying the monthly rainfall in a section of the brazilian rainforest. she recorded the monthly rainfall, in inches, for last year. they were: 10.4, 10.3, 11.7, 11.1, 8.0, 4.4, 2.6, 1.8, 2.5, 4.4, 7.3, 9.5 fill in the missing values in the formula. what is the variance?