plan A charges $20 per month plus 7 cents per minute and plan B charges $26 plus 5 cents per minute.

Question

“For what amounts of monthly phone use will Plan A cost less than Plan B? Use m for the number of minutes of phone use, and solve your inequality for m.”

Answer 1

A cost = 20 + .07m

B cost = 26 + .05m

set them equal

26 + .05m = 20 + .07m

6 = .02m

m = 6/.02 = 300 minutes and both plans cost the same

m< 300 and A is more expensive, B cheaper

m > 300 then A is cheaper, B more expensive