Answer:
52 Hz
Step-by-step explanation:
We can divide the speed by the wavelength to find the number of waves propagated in one second:
(130 m/s)/(2.5 m/wave) = 52 waves/s
The SI unit of frequency is the Hertz, equal to one cycle per second.
The frequency of this wave is 52 Hz.
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<em>Additional comment</em>
The use of the unit Hz to signify frequency was adopted in 1933, but did not replace the unit "cycles per second" (CPS) until a number of years later.
The answer
<span>2x - y + z = -3 (1)
2x + 2y + 3z = 2 (2)
3x - 3y - z = -4 (3)
</span> (1) - (2) 3y +2z =5
3 .(1) - 2.(2) 3y+5z = -1<span>
let 's solve
</span>3y +2z =5
3y+5z = -1<span>
z= - 2, and 3y =5+4=9, y=3, so </span>2x - 3 -2 = -3 implies x= 1
<span>
finally x=1, y=3 and z= -2
proof
</span>2x - y + z = -3?? 2.1 - 3 -2 = -3 (true)<span>
</span>
144 girls , 1/3 = 72 , 2/3 = 144
