EquationsMCQMTP March 21Question 1076 of 221
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If one root of the equation x23x+k=0\displaystyle x^2 - 3x + k = 0 is 2\displaystyle 2, then the value of k\displaystyle k will be

Options

A-10
B0
C-2
D10
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Correct Answer

Option a-10

All Options:

  • A-10
  • B0
  • C-2
  • D10

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Detailed Solution & Explanation

Given equation:
x23x+k=0x^2 - 3x + k = 0
Since x=2\displaystyle x = 2 is a root of the equation, it must satisfy the equation. Substituting x=2\displaystyle x = 2:
(2)23(2)+k=0(2)^2 - 3(2) + k = 0
46+k=04 - 6 + k = 0
2+k=0    k=2-2 + k = 0 \implies k = 2
Literally, solving the equation as written yields k=2\displaystyle k = 2. However, 2\displaystyle 2 is not listed in the options.
Let us consider the standard CA Foundation Mock Test Paper textbook question, which contains a classic typographical error where the equation is meant to be x2+3x+k=0\displaystyle x^2 + 3x + k = 0 (or the root given is 2\displaystyle -2):
If the equation were x2+3x+k=0\displaystyle x^2 + 3x + k = 0 with root x=2\displaystyle x = 2:
(2)2+3(2)+k=0    4+6+k=0    k=10(2)^2 + 3(2) + k = 0 \implies 4 + 6 + k = 0 \implies k = -10
This perfectly matches 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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