The ratio in which the line segment joining the points $A(4,8,10)$ and $B(6,10,-8)$ is divided by the $yz$ -plane is:

In the $yz$ -plane, the $x$ -coordinate is always 0.Let the $yz$ -plane divide $AB$ in the ratio $k:1$.The $x$ -coordinate of the point of division is given by:$x=\frac{k(x_2)+1(x_1)}{k+1}$$0=\frac{k(6)+1(4)}{k+1}⟹6k+4=0⟹k=-4/6=-2/3$.The negative sign indicates external division.Ratio is 2 : 3 externally.