Question

Your cell phone plan charges you $.02 to send a text message and $.07 to recieve a text message. You plan to spend no more than $5 a month text messaging.

a. Write an equation in standard form that models the possible combinations of sent text messages and received text messages.
b. Graph the equation from part (a). Explain what the intercepts of the graph mean in this situation.
c. List three other possible combinations of the number of messages you can send and receive.

Answer 1

(a)
`Y = (2)/(7) X+(500)/(7)`

(b) Here the intercept means that we pay
`(500)/(7)` more than
`(2)/(7) X` for each text message received

(c) 145 text messages sent and 30 messages received

75 text messages sent and 50 messages received

180 text messages sent and 20 messages received

Explanation:

Here we have

X×0.02 + Y×0.07 = 5

Therefore the equation is

`Y = (2)/(7) X+(500)/(7)`

b. Here the intercept means that we pay
`(500)/(7)` more than
`(2)/(7) X` for each text message received

c. Other combinations are

145 text messages sent and 30 messages received

75 text messages sent and 50 messages received

180 text messages sent and 20 messages received.