In 1991, the cost of mailing a 1 oz. first-class letter was 29 cents, and the inflation rate was 4.6%. If the inflation rate stayed constant, the function C(t) = .29(1.046)t would represent the cost of mailing a first-class letter as a function of years since 1991.
1. If the function given holds true, in what year would the cost of mailing a first-class letter reach 60 cents?

Question

In 1991, the cost of mailing a 1 oz. first-class letter was 29 cents, and the inflation rate was 4.6%. If the inflation rate stayed constant, the function C(t) = .29(1.046)t would represent the cost of mailing a first-class letter as a function of years since 1991.
1.	If the function given holds true, in what year would the cost of mailing a first-class letter reach 60 cents?

mathmale · Answer

Just set the given function = to 60 and solve the reulting equation for t.

anonymous · Answer

I got 197.8 = t.