With only two resistors in parallel, it's relatively easy
to calculate their combined equivalent resistance.
R = (their product) / (their sum)
= (18Ω x 23.5Ω) / (18Ω + 23.5Ω)
= (423Ω²) / (41.5Ω)
= 10.2 Ω
Answer:
The magnitude of the force on the wire is 2.68 N.
Explanation:
Given that,
Length of the wire, L = 5 m
Magnetic field, B = 0.37 T
Angle between wire and the magnetic field, 
Current in the wire, I = 2.9 A
We need to find the magnitude of the force on the wire. The magnetic force in the wire is given by :

So, the magnitude of the force on the wire is 2.68 N. Hence, this is the required solution.
What are the answer choices?
Sound level at distance of 15 m is given as 20 dB
so intensity at this distance is given as



now if we move closer to some some distance the sound level is now 50 dB
now the intensity is given as



now we know that



so now the distance from friend must be 47 cm