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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctEasyConceptual

JEE Main 26 February 2021, Shift 1, Maths Q79

Question 79 of 90 in this shift, Maths question 19 of 30, Section A.

Consider the three planes P1:3x+15y+21z=9P_1 : 3x+15y+21z=9, P2:x−3y−z=5P_2 : x-3y-z=5, and P3:2x+10y+14z=5P_3 : 2x+10y+14z=5 Then, which one of the following is true ?
  1. (1)P1P_1 and P2P_2 are parallel.
  2. (2)P1P_1 and P3P_3 are parallel.Official answer
  3. (3)P1,P2P_1, P_2 and P3P_3 all are parallel.
  4. (4)P2P_2 and P3P_3 are parallel.

Official answer

Option 2

NTA final key.

Same idea in other shifts

Asked 2× in all
  1. 3 Aug 2021, Shift 1 · Q76The plane which is parallel to r⃗⋅(i^+2j^+3k^)=6\vec{r} \cdot (\hat{i} + 2\hat{j} + 3\hat{k}) = 6 and passes through (1, 2, 3), also passes through the…EasySingle 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.