Solving the equations we get the means of x and y.
Here it is x=130 and y=90
Rewriting the first equation as y=(1/2)x+25 and second equation as x=(3/2)y-5, and multiplying the coefficients on the right side, we get
(1/2)(3/2)=3/4 which is less than 1.
(otherwise we must consider rewriting the equations the other way)
This value is square of the correlation coefficient. Therefore taking square root, we get the correlation coefficient as
r =root(3)/2=0.866.