Question

The point with position vectors $(2,6),(1,2)$ and $(p,10)$ are collinear if the value of $p$ is

• A. $3$
• B. $-3$
• C. $12$
• D. $6$

Answer 1

The correct option is A $3$

If all three point lies on a line then only condition will hold

So, line passing though $(2,6)$ and $(1,2)$ will be

$(y-2)=(x-1)\left(\frac{6-2}{2-1}\right)⟹y=4x-2$

So, $10=4p-2⟹p=3$