EquationsMCQMTP Apr 21Question 1078 of 221
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Roots of the equation 3x214x+k=0\displaystyle 3x^2 - 14x + k = 0 will be reciprocal of each other if:

Options

Ak=3\displaystyle k = 3
Bk=0\displaystyle k = 0
Ck=3\displaystyle k = -3
Dk=14\displaystyle k = 14
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Correct Answer

Option ak=3\displaystyle k = 3

All Options:

  • Ak=3\displaystyle k = 3
  • Bk=0\displaystyle k = 0
  • Ck=3\displaystyle k = -3
  • Dk=14\displaystyle k = 14

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Detailed Solution & Explanation

Given the equation:
3x214x+k=03x^2 - 14x + k = 0
Let the roots be α\displaystyle \alpha and β\displaystyle \beta. Since the roots are reciprocals of each other, we have:
β=1α    αβ=1\beta = \frac{1}{\alpha} \implies \alpha\beta = 1
From Vieta's formulas, the product of roots for a quadratic equation ax2+bx+c=0\displaystyle ax^2 + bx + c = 0 is given by c/a\displaystyle c/a. Here, a=3\displaystyle a = 3 and c=k\displaystyle c = k:
αβ=k3\alpha\beta = \frac{k}{3}
Equating both expressions for the product of roots:
k3=1    k=3\frac{k}{3} = 1 \implies k = 3
This corresponds to Option a.

**Option a**

About This Chapter: Equations

Paper

Paper 3: Quantitative Aptitude

Weightage

4-6 Marks

Key Topics

Linear, Quadratic and Cubic Equations

This chapter covers Linear, Quadratic and Cubic Equations and is part of Paper 3: Quantitative Aptitude in the CA Foundation exam.

View Official ICAI Syllabus

Exam Strategy Tip

This topic carries 4-6 Marks weightage. Focus on understanding core concepts rather than memorizing.

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