Question

The cost of fun for kids magazine for x number of months is shown below

The cost (C) of another magazine, Family Fun, for x number of months is
given by C-1.99x.

The cost of another magazine, Kidz Comics, is $1.85 for each month. The
annual subscription includes a delivery charge of $10, while the annual
subscription for Fun for kids and Family Fun has no such extra charge
Which annual subscription costs the most?​

Answer 1

Kidz comic costs the most

Explanation:

Given

Family Fun

`C(x) = 1.99x`

Kidz Comics

`m = 1.85` --- monthly rate

`b = 10` --- delivery charge

Required

Which is more expensive

A linear function is represented as:

`f(x) = mx + b`

Where

`m = rate`

`b = y\ intercept` --- i.e. the base charge

So, for Kidz comic; We have:

`f(x) = mx + b`

`C(x) = 1.85x + 10`

To calculate the annual cost, we set x = 12; i.e. 12 months.

So, we have:

`C(x) = 1.99x` ---- Family Fun

`C(12) = 1.99 * 12`

`C(12) = 23.88`

`C(x) = 1.85x + 10` --- Kidz comic

`C(12) = 1.85*12 + 10`

`C(12) = 22.2 + 10`

`C(12) = 32.2`

By comparison

`32.2 > 23.88`

Hence, Kidz comic is more expensive