Given that A (3, 2, –4), B (5, 4, –6) and C (9, 8, –10) are collinear. The ratio in which B divides AC

1 : 2 2 : 1 –1 : 2 –2 : 1

1 : 2

$\frac{9 \lambda+3}{\lambda+1}=5 \Rightarrow 9 \alpha-5 \alpha=2$ $\Rightarrow \lambda=\frac{1}{2}$