Answer:
Equivalent resistance: 13.589 Ω
Explanation:
R series = R1 + R2 + R3 ...

Find the equivalent resistance of the right branch of the circuit:


The wavelength of the note is

. Since the speed of the wave is the speed of sound,

, the frequency of the note is

Then, we know that the frequency of a vibrating string is related to the tension T of the string and its length L by

where

is the linear mass density of our string.
Using the value of the tension, T=160 N, and the frequency we just found, we can calculate the length of the string, L:
Answer: When fire stopping material is used where more than 2 non-metallic sheathed cables pass through wood framing members, their ampacities must be adjusted, according to 310.15"
Answer is 2