Please help me out with the length on this sound intensities problem

[jvirus872000]

Homework Statement

When sounded separately, two identical car horns produce sound intensities at your ear in the ratio 6:1. If the nearer car is 8m from you, how far from you is the more distant car? Assume uniform spherical wavefronts.

Homework Equations

Intensity=P/4x(3.14)"pi"x R^2
ratio fartest car=(ratio nearest car+ratio that i am)^1/2<<"squareroot"

The Attempt at a Solution

All I did was the surface area for the sphere, which was
4x3.14x8^2= 1607.7
Then i do not know what else to do because i need to find the length, I know the answer should be 19.6

 

[LowlyPion]

Welcome to PF.

I ∝ 1/r²

So the ratio of I₁/I₂ = R₂² /R₁²

That suggests then that

6/1 = R²/8² then isn't it?