Question about Sound an intensiy

[cfl25]

Homework Statement

A speaker delivers 500Hz sound at an intensity of 4.0x10^-4 W/m² when measured at a distance of 1.0m from the speaker. At what distance from the speaker would you have to be to hear 4000Hz sound at the same perceived loudness?

Homework Equations

The Attempt at a Solution

I keep getting very short distances that do not make sense. If i could get some help on how to start this it would be great.

 

[rl.bhat]

Intensity is proportional to the square of frequency. So find the intensity at 1m due to the source of 4000 Hz. Then using inverse square law find the distance where the intensity well be 4x10^-4 W/m^2