Question

The wavelength of a radio wave varies inversely as its frequency. A wave with a frequency of 720 kilohertz has a length of 500 meters. What is the length of a wave with a frequency of 450 kilohertz?
.......... meters

Answer 1

Answer:

800 meters

Step-by-step explanation:

y is inversely proportional to x is the same as y is inversely proportional to $\frac{1}{x},$ that means

$y=\dfrac{k}{x}.$

If a wave with a frequency of x=720 kilohertz has a length of y=500 meters, then

$500=\dfrac{k}{720}\\ \\k=500\cdot 720=360000.$

Hence, the length of a wave y with a frequency of x=450 kilohertz is

$y=\dfrac{360000}{450}=800$