A real estate agent is considering changing her cell phone plan; there are three to chose from - all involve a monthly fee of $20.25
Plan A charges $0.51 per minute for daytime calls and $0.15 per minute for evening calls.
Plan B charges $0.59 per minute for daytime calls and $0.18 per minute for evening calls.
Plan C has a flat rate of $50 with up to 200 minutes of calls included per month and a charge of $0.34 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?