To solve the problem it is necessary to apply the concepts related to sound intensity. The most common approach to sound intensity measurement is to use the decibel scale:

Where,
is a reference intensity. It is the lowest or threshold intensity of sound a person with normal hearing can perceive at a frequency of 1000 Hz.
I = Sound intensity
Our values are given by,


For each auto the intensity would be,




Therefore the sound intesity for the 7 autos is


The sound level for the 7 cars in dB is


S= 343m/s
F=256Hz
WL= 343ms/256-1
WL=V/F
= 1.339844m
IMA stands for ideal mechanical advantage, which is the theoretical force amplification factor on an ideal mechanical device free of friction, deformations, etc.
If the applied force (effort) is 50N, then the force applied to the resistance is multiplied by the IMA=2 to get 100N.