The amount of the bill is dependent on the number of texts sent. Let y be the bill amount and x the number of texts. Then x is independent and y is dependent. This is because x can be any non-negative number, but y depends upon it. You cannot find the bill without knowing the number of text messages, right?
the dependent variable is defined as a variable which changes depending on the other variables that are manipulated in a function so what that means is that the inputs are independent variables and the outputs are the dependent variables and in the case of this question the amount of texts sent are the independent variables and the amount charged is the dependent variable
