### Home > A2C > Chapter 8 > Lesson 8.2.2 > Problem8-131

8-131.

The average cost of movie tickets is $9.50$. If the cost is increasing 4% per year, in how many years will the cost double?

Construct a representation of this scenario using the generic exponential equation:
$y = ab^{x}$

Solve for $x$ (the number of years):
$2\left(9.50\right) = 9.50\left(1.04\right)^{x}$

$\approx17.67\ \text{years}$