Answer:
40 units
Explanation:
Let y be the strength for the radio signal.
Let x be the distance from the transmitter.
If the strength for the radio signal varies inversely with the square of the distance from the transmitter, then:

where k is the constant of proportionality.
Given the strength is 1000 units at a distance of 2km:
Substitute the values into the equation and solve for k:



Therefore, the equation that links y and x is:

To find the strength (y) at a distance (x) of 10 km from the transmitter, substitute x = 10 into the equation:



Therefore, the strength of the radio signal at a distance of 10 km from the transmitter is 40 units.