Question

Ben has a cellphone plan where he pays $12 per month plus $.10 per minute of talk time. The equation y=0.1x+12 can be used to find his monthly phone bill y given the number of minutes x he is talking. Which of the following, in set builder notation, represents a reasonable range of the function.

Answer 1

A reasonable range for the function y=0.1x+12 would be all real numbers greater than or equal to 12. This is because the minimum monthly phone bill that Ben could have would be $12 (if he does not use any minutes), and the monthly bill can increase to any higher value depending on the number of minutes he talks. In set builder notation, this range would be written as y >= 12.

Explanation: