Question

a 12 - pound weight attached to a spring stretches the spring by 2 inches. how many inches will the spring stretch if the 12 - pound weight is replaced with an 18 - pound weight?
a 2
b 3
c 4
d 6

Explanation:

Step1: Set up proportion

Let \( x \) be the stretch for 18 - pound weight. The relationship between weight and stretch is proportional, so \(\frac{12}{2}=\frac{18}{x}\).

Step2: Solve for \( x \)

Cross - multiply: \( 12x = 18\times2 \).
Simplify right - hand side: \( 12x = 36 \).
Divide both sides by 12: \( x=\frac{36}{12}=3 \).

Answer:

B. 3