Pls help 50 points :) and brainliest to person who responds first
On Naomi's cell phone plan, the amount she pays each month for international text messages is proportional to the number of international texts she sends that month. Last month, she paid $3.20 for 16 international texts.

A. What is the constant of proportionality in this proportional relationship?
B. Write an equation to represent this proportional relationship. Make sure to define the variables you use.