A real estate agent is considering changing her cell phone plan. There are three plans to choose from. Plan A and B involve a monthly fixed charge of $25. Plan A has a cost of $0.50 a minute for daytime and $0.20 a minute for evening calls. Plan B has a charge of $0.65 a minute for daytime calls and $0.15 a minute for evening calls. Plan C has a flat rate of $150 with 150 minutes of calls allowed per month and a charge of $0.45 per minute beyond that, day or evening.

Determine the total charge under each plan for this case: 300 minutes of day calls and 200 minutes of evening calls in a month.

I know that for Plan A and Plan B , the total cost is obtained by adding the monthly fixed to the minutes multiplied by the day and night rate. So $215 and $250. Whats the formula/how can I obtain the total cost for Plan C? It should be $307.50