What is the equation for the line of reflection? pls help

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?

An engineer scale model shows a building that is 3 inches tall. if the scale is 1 inch = 600 feet, how tall is the actual building?

During the election for class president, 40% of the students voted for kellen, and 60% of the students voted for robbie. 500 students voted in total. how many more students voted for robbie than for kellen? answer with work : )