To find the probability that the price is between $80 and $90, we need to integrate the probability density function $f(x)$ from 80 to 90. $P(80 \leq x \leq 90) = \int_{80}^{90} \frac{x}{5000} dx = \left[ \frac{x^2}{10000} \right]_{80}^{90}$ $P(80 \leq x \leq 90) = \frac{90^2 - 80^2}{10000} = \frac{8100 - 6400}{10000} = \frac{1700}{10000} = 0.17$ or $17%$