JEE Main 2020 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 9 January 2020, Shift 1, Maths Q55

Question 55 of 75 in this shift, Maths question 5 of 25, Section A.

If for some

\alpha

and

\beta

\mathbf{R}

, the intersection of the following three planes

x+4y-2z=1

x+7y-5z=\beta

x+5y+\alpha z=5

is a line in

\mathbf{R}^3

, then

\alpha+\beta

is equal to :

(1) $-10$
(2)0
(3)2
(4)10Official answer

Official answer

Option 4

NTA final key (Jan 2020).

Chapter: Determinants
Topic: Cramer's Rule
Idea tested: Evaluating Parameters for Consistency

Same idea in other shifts

Asked 15× in all

2 Apr 2025, Shift 2 · Q4If the system of equations $2x + \lambda y + 3z = 5$ $3x + 2y - z = 7$ $4x + 5y + \mu z = 9$ has infinitely many solutions, then…MediumSingle correct
7 Apr 2025, Shift 1 · Q4Let the system of equations : $2x + 3y + 5z = 9$ , $7x + 3y - 2z = 8$ , $12x + 3y - (4+\lambda)z = 16 - \mu$ , have infinitely many…MediumSingle correct
7 Apr 2025, Shift 2 · Q5Let the system of equations $x+5y-z=1$ $4x+3y-3z=7$ $24x+y+\lambda z=\mu$ $\lambda,\mu\in\mathbf{R}$ , have infinitely many solutions. Then…HardSingle correct
1 Feb 2024, Shift 2 · Q5Let the system of equations $x+2y+3z=5$ , $2x+3y+z=9$ , $4x+3y+\lambda z=\mu$ have infinite number of solutions. Then $\lambda+2\mu$ is…MediumSingle correct
30 Jan 2024, Shift 1 · Q3Consider the system of linear equations $x+y+z=4\mu$ , $x+2y+2\lambda z=10\mu$ , $x+3y+4\lambda^2z=\mu^2+15$ , where…MediumSingle correct
6 Apr 2023, Shift 2 · Q5For the system of equations $x+y+z=6$ $x+2y+\alpha z=10$ $x+3y+5z=\beta$ , which one of the following is NOT true?MediumSingle correct
11 Apr 2023, Shift 2 · Q4If the system of linear equations $7x + 11y + \alpha z = 13$ $5x + 4y + 7z = \beta$ $175x + 194y + 57z = 361$ has infinitely many…MediumSingle correct
13 Apr 2023, Shift 1 · Q4For the system of linear equations $2x+4y+2az=b$ $x+2y+3z=4$ $2x-5y+2z=8$ which of the following is NOT correct?MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.