A real estate agent is considering changing her cell phone plan; there are three to chose from - all involve a monthly fee of $19.50
Plan A charges $0.35 per minute for daytime calls and $0.15 per minute for evening calls.
Plan B charges $0.57 per minute for daytime calls and $0.16 per minute for evening calls.
Plan C has a flat rate of $34 with up to 200 minutes of calls included per month and a charge of $0.38 per minute beyond that, day or evening.
If the agent will use the service for daytime calls only, how many minutes per month should she stay below so that Plan A is the least cost alternative?