### Home > AC > Chapter 13 > Lesson 13.IF2-S > Problem 6-31

6-31.

Barnaby’s grandfather is always complaining that back when he was a teenager, he used to be able to buy his girlfriend dinner for only

If that same dinner that Barnaby’s grandfather purchased for

sixty years ago now costs , and the price has increased exponentially, write an equation that will give you the costs at different times. Begin by defining variables.

Letthe number of years

Letthe cost of a dinner

You need to write an equation of the form.Use the points

and to write and solve a system of equations. How much would you expect the same dinner to cost in 60 years?

Let

in your equation from part (a).