Q.

If the shortest distance between the lines x–41=y+12=z–3 and x–λ2=y+14=z–2–5 is 65, then the sum of all possible values of λ is :          [2024]

1 5  
2 7  
3 8  
4 10  

Ans.

(3)

Here x1=4, y1=–1, z1=0 and x2=λ, y2=–1, z2=2

a1=1, b1=2, c1=–3 and a2=2, b2=4, c2=–5

∵  65=||λ–40212–324–5|(–10+12)2+(–6+5)2+(4–4)2|

⇒ 65=|2λ–85|⇒ λ=7 or 1.