Let L be the line x+1 2= y+1 3= z+3 6 and let S be the set of all points ( a, b, ) on L, whose distance from the line x+1 2= y+1 3= z-9 0 along the…
JEE Main 2026 — Mathematics Vectors & 3D Geometry
2026mcqhard
Let L be the line 2x+1=3y+1=6z+3 and let S be the set of all points (a,b,c) on L, whose distance from the line 2x+1=3y+1=0z−9 along the line L is 7. Then (a,b,c)∈S∑(a+b+c) is equal to :
Official previous-year question
Held on 22 Jan 2026 · Verified 6 Jul 2026.
Options
A
6
B
34
C
40
D
28
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Solution
M is the point of intersection of L1 & L2
⇒2λ−1=2μ−1,3λ−1=3μ−1,6λ−3=9
⇒λ=2=μ
⇒M(3,5,9)
Now let point P be (2K−1,3K−1,6K−3) on L2
such that PM=7
⇒(2K−4)2+(3K−6)2+(6K−12)2=7
⇒49K2+196−196K=49
⇒K2+4−4K=1
⇒K2−4K+3=0
⇒K=1,3
So points P & Q are (1,2,3) & (5,8,15)
So sum of all co-ordinates of P & Q =34
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