the half life of a substance is defined as the period of time it takes for the amount of the substance to decay by half. the sequence below shows the amount of a substance that will be left after a certain number of half lives have elapsed.

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.