The frequency f of vibration of a string in stringed instrument varies inversely with the length l (in inches) of the string (as the string shrinks, the frequency grows)

Question

A C string that is 12 inches long vibrates at 600Hz. If the D string is 9 inches long, what is the frequency of vibration?

A) 450Hz

B) 800Hz

C) 900Hz

D) 1200Hz

Answer 1

12(600) = 9f

4(600) = 3f

4(200) = f

800 = f