Question

The length of a spring is a linear function of the weight of the object compressing it. For a particular spring, the length decreases by 1.5 inches for every 3 pounds pressing down on it. When 4 pounds are on the spring, the length of the spring is 8 inches long. What is the length of the spring if 15 pounds are pressing down on the spring?

Answer 1

2.5 inches long because 15-4=11 and 11/3=3.6666667 and 3.6666667x1.5=5.5. Therefore, the spring decreased another 5.5 inches from 8 inches so the spring would now be 2.5 inches long.