Question

A cell phone company is offering its customers the following deal: You can buy a new cell phone for $60 and pay a monthly flat rate of $40 per month for unlimited calls. The function y=40x+60 represents the total cost per month. How much money will this deal cost you after 9 months? How much would it cost for 0 months?

Answer 1

Cost after 9 months = $420

Cost for 0 months = $60

Explanation:

Given that:

Cost of new cell phone = $60

Cost for unlimited calls per month = $40

Function to represent the total cost per month:

`y = 40x+60` ..... (1)

where y is the total cost and

x is the number of months.

To find:

Total cost after 9 months and 0 months.

Solution:

Let us put the value
`x = 9` in the above equation (1)

`y = 40 * 9 +60\\\Rightarrow y = 360 +60\\\Rightarrow y = \$420`

Hence, cost after 9 months = $420.

Cost after 0 months i.e. put the value
`x = 0` in the above equation (1)

`y = 40 * 0 +60\\\Rightarrow y = 0+60\\\Rightarrow y = \$60`

i.e. only cell phone is bought no cost for call is given.

Cost for 0 months is equal to the cost of cell phone.

So, the answers are:

Cost after 9 months = $420

Cost for 0 months = $60