Q.

If the shortest distance between the lines x41=y+12=z3 and xλ2=y+14=z25 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=||λ402123245|(10+12)2+(6+5)2+(44)2|

 65=|2λ85| λ=7 or 1.