When building a house, the number of days required to build varies inversely with the number of workers. One house was built in 21 days by 19 workers. How many days would it take to build a similar house with 7 workers

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.