Question

There are two cell phone plans available from Cells Phones R Us company. Plan A charges $35 a month plus $0.05 for every text message. Plan B charges $50 a month plus $0.01 for every text message. How many text messages do you need to send in order for Plan A to cost the same as Plan B?

Answer 1

if PLAN A is cheaper than PLAN B then,

P (A) < P (B)

30+0.01t < 20+0.05t      (subtract 0.05t from both sides)

29.95-0.04t < 19.95        (subtract 29.95 from both sides)

-0.04t < -10                      (divide both sides by -0.04)

t > 250

So plan A is cheaper than plan B when you send more than 250 texts.

Hope it helps.