# Math Help - Function Notation word problem

1. ## Function Notation word problem

Just looking for someone to get me started, as I am absolutely lost on these problems:

The purchase of a "collector's item" is often made in hopes the item will increase in value. In 1998, Mark purchases a 1909-S VDB Lincoln Cent(in fair condition) for $150. By the year 2004, its value has grown to$190.

a) Use the relation(time since purchase,penny's value C) with t = 0 corresponding to 1998 to find a linear equation modleing the value of the coin

b) How much will the penny be worth in 2009?

c) How many years after the purchase will the penny's value exceed $250? d) If the penny is now worth$170, how many years has Mark owned the penny?

Any help would be appreciated!

2. in 6 years, the value has increased $40. if the value increases at the same rate, then ... $\displaystyle V = 150 + \frac{40}{6} \cdot t$ ... where $V$ is the value in$ and $t$ is the time in years since 1998.

part (a) is done ... now answer the other questions.

3. Thanks...I was definitely over thinking it!

4. the value of the coin has increased $190 -$150 = $40 over six years. How much does it increase per year? This will give you the gradient of your equation. The value of the coin at t=0 is$150, this gives you the constant.
your equation will be in the form C(value) = m(gradient) *t(# years since 1998) + c(constant)

Once you have this, b-d will simply be a matter of re-arranging this equation to isolate variables