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Day 570: JEE Mains Maths

5 questions. Try each one first, then open its answer.

  1. Question 1

    Matrices. Asked once: 29 Jul 2022

    152
    Which of the following matrices can NOT be obtained from the matrix [−121−1]\begin{bmatrix} - 1 & 2 \\ 1 & - 1 \end{bmatrix} by a single elementary row operation?

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  2. Question 2

    Permutations and Combinations. Asked once: 2021 Paper 24

    76
    Let P1,P2,…..,P15P_{1},P_{2},\ldots..,P_{15} be 15 points on a circle. The number of distinct triangles formed by points Pi,Pj,PkP_{i},P_{j},P_{k} such that i+j+k≠15i + j + k \neq 15, is:

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  3. Question 3

    Probability. Asked once: 14 Jun 2022

    178
    In an examination, there are 10 true-false type questions. Out of 10, a student can guess the answer of 4 questions correctly with probability 34\frac{3}{4} and the remaining 6 questions correctly with probability 14\frac{1}{4}. If the probability that the student guesses the answers of exactly 8 questions correctly out of 10 is 27k410\frac{27k}{4^{10}}, then kk is equal to

  4. Question 4

    Quadratic Equations. Asked once: 26 Jul 2022

    81
    If for some p,q,r∈Rp,q,r \in R, not all have same sign, one of the roots of the equation (p2+q2)x2−2q(p+r)x\left( p^{2}+q^{2} \right)x^{2}- 2q(p + r)x +q2+r2=0+q^{2}+r^{2}= 0 is also a root of the equation x2+2x−8=0x^{2}+ 2x - 8 = 0, then q2+r2p2\frac{q^{2}+r^{2}}{p^{2}} is equal to-

  5. Question 5

    Relations and Functions. Asked once: 27 Jul 2022

    172
    The number of functions ff, from the set A={x∈N:x2−10x+9≤0}A =\left\{ x \in N:x^{2}- 10x + 9 \leq 0 \right\} to the set B={n2:n∈N}B =\left\{ n^{2}:n \in N \right\} such that f(x)≤(x−3)2+1f(x) \leq (x - 3)^{2}+ 1, for every x∈Ax \in A, is