Explanation

(b)
Let us assume that line of regression y on x is $3x + 12y = 19\ and\ x\ on\ y\ is\ 3y + 9x = 46.$
${\therefore b_{yx} = - \frac{3}{12}and\ b_{xy} = - \frac{3}{9} = - \frac{1}{3}
}{\therefore r_{xy} = - \sqrt{b_{yx} \times b_{xy}} = - \sqrt{\left( \frac{3}{12} \right) \times \left( \frac{1}{3} \right)}}$
$= - \sqrt{\frac{1}{12} = - \sqrt{0.083}}$
$= - 0.289$