Question

A real estate agent is considering changing her cell phone plan; there are three to chose from - all involve a monthly fee of $17.50

Plan A charges $0.47 per minute for daytime calls and $0.18 per minute for evening calls.

Plan B charges $0.55 per minute for daytime calls and $0.19 per minute for evening calls.

Plan C has a flat rate of $46 with up to 200 minutes of calls included per month and a charge of $0.39 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?

Answer 1

		Per Minute (Day time) $	Per Minute (Night time) $	Only Day time Calls Tariff (Assume "a" number of minutes per day)
Plan A		0.47	0.18	a x 0.47
Plan B		0.55	0.19	a x 0.55
Plan C	$46 for 200 minutes of calls	0.39	0.39
As Plan B Tariff is higher than A, we no need to check against Plan B
So we need to check the total number of calls at which Plan A total tariff is less than Plan C
Also number of calls should be less than 200 as beyond 200 tariff of Plan C is less than Plan A
	a x 0.47 < ($46)
	a<97.9
So if the real estate agent make calls for less than or equal to 97 minutes plan A is benefical for him