College Algebra Word Problem

Question

A painting sold for $270 in 1975 and was sold again in 1986 for $ 411. Assume that the growth in the value V of the collector's item was exponential.
a) Find the value k of the exponential growth rate. Assume Upper Vo=270.

Answer 1

411 = 270e^9k

411/270 = 137/9 = e^9k

ln(137/9) = 9k

k = ln(137/9)/9

k = .0467 = 4.67 % growth rate per year