Answer: the spring would be stretched by 38 inches.
Step-by-step explanation:
The length that a hanging spring stretches varies directly with the weight placed at the end of the spring. Let L represent the length of the spring and let w represent the weight placed at the end of the spring. Introducing a constant of variation, k, the expression would be
L = kW
If a weight of 15lb stretches a certain spring 19in, the expression would be
19 = 15k
k = 19/15
The equation would be
L = 19w/15
if the weight is increased to 30lb, then the length by which the spring would be stretched is
L = 19 × 30/15
L = 38 inches
