Question 666941: Your cell phone company offers two text-messaging plans. One plan costs $.25 per text message, plus a monthly fee of $9. The other plan costs $.40 per text message with no monthly fee.
a. For how many text messages will both plans cost the same amount?
b. Reasoning - If you use about 80 text messages each month, which plan should you choose? explain.
Have been trying for the last 1/2 hour but totally lost.
Answer by MatrixWoman(6)   (Show Source):
You can put this solution on YOUR website! y=.25x+9 is plan a
y=.40x is plan b
put the two equations to equal each other so:
.25x+9=.40x
take the 9 and subtract it to the .40 side and subtract the .40x with the.25 and get -.15 take -9 divided by -.15 and get 60.
x=60 text messages
then for part b) plug in 80 to both equations, and see which answer is bigger, you do not want the bigger answer because that means you are spending more money so plugging in 80 for x into the first equation it was 29 for the second equation it was 32 thus meaning that the first equation is the better option.
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