1.4. (10%) The data consists of n independently selected pairs $(X_i, Y_i), i=1,2,\dots,n$. The linear regression line of Y on X is $\hat{Y} = 30 - 1.5X$. The linear regression line of X on Y is $\hat{X} = 12 - 0.54Y$. What is the absolute value of Pearson correlation coefficient between variables X and Y?