<image>A university student is preparing to sell a type of pencil case during the school start season to try entrepreneurship. In one school start season, a profit of 30 yuan is made for each unit sold, and a loss of 10 yuan is incurred for each unsold unit. Based on historical data, a frequency distribution histogram of the market demand during the school start season is obtained, as shown in the figure. This student has purchased 160 units of the product for this school start season. Let \( x \) (unit: units, \( 100 \leq x \leq 200 \)) represent the market demand during this school start season, and let \( y \) (unit: yuan) represent the profit from selling this product during the school start season.

(1) Based on the histogram, estimate the mode and mean of the market demand \( x \) during this school start season.
(2) Express \( y \) as a function of \( x \).
(3) Based on the histogram, estimate the probability that the profit \( y \) is no less than 4,000 yuan.