If the concession stand sold 4200 hot dogs at the ball game and each person bought 2 hot dogs how many people bought hot dogs?

Can someone explain to me how to do

50 points~ ! i have to turn this in tomarrow

The bottom of ignacio's desktop is 74.5cm from the floor. ignacios sits in his adjustable chair, and the tops of his legs are 49.3cm from the floor. each clockwise rotation of the knob on the chair raises ignacio's legs by 4.8cm. write an inequality to determine the number of clockwise rotations, r, ignacio could make with the knob without his legs touching the desk.