Let the line segment joining the points A(–2, 4, 7) and B(3, –5, 8) be divided by the yz-plane at a point C in the ratio k : 1. ∴ Coordinates of C are $\left(\frac{3k-2}{k+1}, \frac{-5k+4}{k+1}, \frac{8k+7}{k+1}\right)$ Since the point C lies on YZ-plane. So X = 0 ∴ $\frac{3k-2}{k+1}$ = 0 ⇒ 3k - 2 = 0 ⇒ k = $\frac{2}{3}$ Thus the required ratio is $\frac{2}{3}$ : 1 i.e., 2 : 3