All Exams Test series for 1 year @ ₹349 only
Question

Find the value of k if 13 - [10 - {16 + 8 ÷ (k - 2)} + 2] = 20.

This question was previously asked in
SSC CGL 2023 (Tier-II) Paper 1 Previous Year Paper (26-Oct-2023) (Shift-1)
The correct answer is \(\frac{14}{3}\)

Solving the Equation for the Value of k

The question asks us to find the value of the variable \(k\) in the given mathematical equation: \(13 - [10 - \{16 + 8 \div (k - 2)\} + 2] = 20\). To solve for \(k\), we need to isolate \(k\) by simplifying the equation step by step, following the order of operations (often remembered by acronyms like BODMAS or PEMDAS).

Step-by-Step Solution to Find k

Let's break down the equation and solve it systematically:

The given equation is:

\(13 - [10 - \{16 + 8 \div (k - 2)\} + 2] = 20\)

Step 1: Isolate the main bracket term

First, move the term outside the outermost square bracket to the right side of the equation:

\(- [10 - \{16 + 8 \div (k - 2)\} + 2] = 20 - 13\)
\(- [10 - \{16 + 8 \div (k - 2)\} + 2] = 7\)

Now, multiply both sides by -1 to remove the negative sign outside the square bracket:

\(10 - \{16 + 8 \div (k - 2)\} + 2 = -7\)

Step 2: Simplify inside the square bracket

Combine the constant terms inside the square bracket (which are now on the left side):

\((10 + 2) - \{16 + 8 \div (k - 2)\} = -7\)
\(12 - \{16 + 8 \div (k - 2)\} = -7\)

Step 3: Isolate the curly brace term

Move the constant term \(12\) to the right side of the equation:

\( - \{16 + 8 \div (k - 2)\} = -7 - 12 \)
\( - \{16 + 8 \div (k - 2)\} = -19 \)

Multiply both sides by -1 to remove the negative sign outside the curly brace:

\( 16 + 8 \div (k - 2) = 19 \)

Step 4: Isolate the division term

Move the constant term \(16\) to the right side of the equation:

\( 8 \div (k - 2) = 19 - 16 \)
\( 8 \div (k - 2) = 3 \)

Rewrite the division as a fraction:

\(\frac{8}{k - 2} = 3\)

Step 5: Solve for k

Multiply both sides of the equation by \((k - 2)\) to remove the denominator:

\( 8 = 3 \times (k - 2) \)
\( 8 = 3k - 6 \)

Add 6 to both sides of the equation:

\( 8 + 6 = 3k \)
\( 14 = 3k \)

Finally, divide both sides by 3 to find the value of \(k\):

\( k = \frac{14}{3} \)

Thus, the value of \(k\) that satisfies the given equation is \(\frac{14}{3}\).

Verification (Optional but Recommended)

To verify the solution, substitute \(k = \frac{14}{3}\) back into the original equation:

\(13 - [10 - \{16 + 8 \div (\frac{14}{3} - 2)\} + 2]\)

Calculate the term inside the parenthesis:

\(\frac{14}{3} - 2 = \frac{14}{3} - \frac{6}{3} = \frac{14 - 6}{3} = \frac{8}{3}\)

Now substitute this back:

\(13 - [10 - \{16 + 8 \div (\frac{8}{3})\} + 2]\)

Perform the division:

\(8 \div \frac{8}{3} = 8 \times \frac{3}{8} = 3\)

Substitute this back:

\(13 - [10 - \{16 + 3\} + 2]\)

Simplify inside the curly braces:

\(13 - [10 - \{19\} + 2]\)

\(13 - [10 - 19 + 2]\)

Simplify inside the square brackets:

\(10 - 19 + 2 = -9 + 2 = -7\)

Substitute this back:

\(13 - [-7]\)

\(13 + 7 = 20\)

The left side equals 20, which matches the right side of the original equation. Thus, the value \(k = \frac{14}{3}\) is correct.

Revision Table: Equation Solving Steps

StepActionEquation
1Original Equation\(13 - [10 - \{16 + 8 \div (k - 2)\} + 2] = 20\)
2Isolate outermost bracket\(-[10 - \{16 + 8 \div (k - 2)\} + 2] = 7\)
3Remove negative sign\(10 - \{16 + 8 \div (k - 2)\} + 2 = -7\)
4Simplify inside square bracket\(12 - \{16 + 8 \div (k - 2)\} = -7\)
5Isolate curly brace term\( - \{16 + 8 \div (k - 2)\} = -19 \)
6Remove negative sign\( 16 + 8 \div (k - 2) = 19 \)
7Isolate division term\( 8 \div (k - 2) = 3 \)
8Rewrite division\(\frac{8}{k - 2} = 3\)
9Solve for k\( 8 = 3k - 6 \)
10Isolate 3k\( 14 = 3k \)
11Final value of k\( k = \frac{14}{3} \)

Additional Information: Order of Operations (BODMAS/PEMDAS)

Solving equations like this requires strictly following the order of operations. This ensures that we simplify the expression correctly. The acronyms BODMAS and PEMDAS help remember this order:

  • BODMAS: Brackets, Orders (powers, square roots), Division and Multiplication (from left to right), Addition and Subtraction (from left to right).
  • PEMDAS: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).

In our problem, we started with the innermost parentheses/brackets `(k-2)`, although we couldn't simplify that directly. We then worked outwards from the curly braces `{}` to the square brackets `[]`, performing operations in the correct order (division before addition/subtraction). Finally, we used inverse operations (subtraction/addition, multiplication/division) to isolate the variable \(k\).

Was this answer helpful?

Similar Questions

  1. The value of 1800 ÷ 20 × {(12 - 6) + (24 - 12)} is:

  2. If ‘A’ stands for ‘subtraction’, ‘B’ stands for ‘multiplication’, ‘C’ stands for ‘addition’ and ‘D’ stands for ‘division’, then what is the value of the following expression?

    32 B 4 A 12 B (35 A 24) C 52 D 4
  3. What is the value of 9991 × 10009?

  4. The value of 3.8 – (4.2 ÷ 0.7 × 3) + 5 × 2 ÷ 0.5 is∶

  5. The value of 15.2 + 5.8 ÷ 2.9 × 2 - 3.5 × 2 ÷ 0.5 is equal to:

  6. The value of 16 ÷ 4 of 4 × [3 ÷ 4 of {4 × 3 ÷ (3 + 3)}] ÷ (2 ÷ 4 of 8) is:

  7. Evaluate the following:

    5 - [96 ÷ 4 of 3 - (16 - 55 ÷ 5)] = ?

  8. The value of (26 - 13 × 2) ÷ 2 + 1 is:

  9. Solve the following expression.

    5.6 – {2 + 0.6 of (2.1 – 2.6 × 1.12)}
  10. The value of \(1\frac{1}{8} \div \left( {4\frac{1}{4} \div \frac{3}{5}of\;8\frac{1}{2}} \right) - \frac{2}{5} \times 1\frac{1}{3} \div \frac{4}{5}of\;1\frac{2}{3} + \frac{{11}}{{20}}\) is:


Important Questions from Bodmas Rule

  1. Solve: {7.88 × 2 + 2.4 × 5 - 242.4 ÷ 4 + [9.2 × 4 - 2.46 of 3 + (36.3 ÷ 3 - 1.42 × 2)]} 

  2. What will come in the place of question mark (?) in the given expression?

    (420 ÷ 12 × 35 + 452- 152) = ?2

  3. What will come in place of the question mark ‘?’ in the following question?

    (44 of 15) – [(450 × 240 ÷ 60 – 40) ÷ 80 × 25 + 50] – 10 = ?
  4. Simplify: 92 - 18 ( 9 + 36 ÷ 3 × 12 - 27 × 3) + 51

  5. Simplify the following expression.

    \(\rm \frac{3}{5}\ of\ \left\{\left(48\div\overline{36\div9}\times\frac{1}{6}\right)+\frac{1}{3}\right\}=?\)

Need Expert Advice?
Upcoming Exams
SSC JE
November 02, 2026
SSC CPO
November 23, 2026
SSC CHSL
November 30, 2026
Test Series
SSC CGL img
SSC
SSC CGL (Tier I + Tier II) 2026 Mock Test Series - Latest Pattern
2509 Tests 6 Tests Free
8786 Attempts
4.2(941)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App