quant. methods
posted by Christina .
Kim is deciding between two cell phone plans. Plan A charges a fixed monthly fee of $100 for 1200 minutes and .25 per minute over 1200. Plan B charges a fixed monthly fee of $55 for 1000 minutes and .33 per minute over 1000. At what point of usage would Kim be indifferent between the two plans?

100 + .25 (x1200) = 55 + .33(x1000)
Solve for x. 
cant be

gotta be!

yes but how could it be 937.50 minutes when you will pay 100 or 55 dollars either way for 1200 or 1000 minutes. It would need to be over those minutes.