Question

C=12.90+0.11t how many text messages can Malcolm send and receive for $20

Answer 1

The function for the cost of text messages is given by:

`c=12.90+0.11t`

If we have a total cost of $20, we then can solve for the number of text messages:

`20=12.90+0.11t\Rightarrow20-12.90=0.11t`

Dividing both sides of the equation by 0.11, we have:

`(7.1)/(0.11)=t\Rightarrow t=64.5454\ldots`

That is, for $20, Malcolm is able to send and receive about 64 message.