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Question

What will come in place of '?' in the following equation?

\(4 + \frac{1}{6} \times \left[ {\left\{ { - 12 \times \left( {24 - 12 - 4} \right)} \right\} \div \left( {20 - 4} \right)} \right] = \;?\)

This question was previously asked in
RRB ALP 2018 CBT 2 Fitter Question Paper (21-Jan-2019) (Shift 3)
The correct answer is

3

Solving the Given Mathematical Equation

The question asks us to find the value that replaces the '?' in the given equation:

\(4 + \frac{1}{6} \times \left[ {\left\{ { - 12 \times \left( {24 - 12 - 4} \right)} \right\} \div \left( {20 - 4} \right)} \right] = \;?\)

To solve this equation, we need to follow the order of operations, often remembered by the acronyms BODMAS or PEMDAS.

Understanding the Order of Operations (BODMAS/PEMDAS)

This rule dictates the sequence in which mathematical operations should be performed:

  • Brackets (or Parentheses)
  • Orders (or Exponents)
  • Division and Multiplication (from left to right)
  • Addition and Subtraction (from left to right)

Let's simplify the expression step-by-step according to this rule.

Step-by-Step Solution to the Equation

We start by simplifying the innermost brackets.

Step 1: Simplify the innermost Parentheses

The equation contains two sets of innermost parentheses:

  • \((24 - 12 - 4)\)
  • \((20 - 4)\)

Let's calculate their values:

  • \((24 - 12 - 4) = (12 - 4) = 8\)
  • \((20 - 4) = 16\)

Substitute these values back into the equation:

\(4 + \frac{1}{6} \times \left[ {\left\{ { - 12 \times 8} \right\} \div 16} \right]\)

Step 2: Simplify the Curly Braces

Next, we simplify the expression inside the curly braces, which is a multiplication:

  • \({ - 12 \times 8 } = -96\)

Substitute this value back into the equation:

\(4 + \frac{1}{6} \times \left[ {-96 \div 16} \right]\)

Step 3: Simplify the Square Brackets

Now, simplify the expression inside the square brackets, which is a division:

  • \({-96 \div 16} = -6\)

Substitute this value back into the equation:

\(4 + \frac{1}{6} \times [-6]\)

Step 4: Perform the Multiplication

According to BODMAS, multiplication comes before addition. Perform the multiplication:

  • \(\frac{1}{6} \times -6 = -\frac{6}{6} = -1\)

Substitute this value back into the equation:

\(4 + (-1)\)

Step 5: Perform the Addition

Finally, perform the addition:

  • \(4 + (-1) = 4 - 1 = 3\)

Final Result

The value that comes in place of '?' is 3.

The simplified equation is:

\(4 + \frac{1}{6} \times \left[ {\left\{ { - 12 \times \left( {24 - 12 - 4} \right)} \right\} \div \left( {20 - 4} \right)} \right] = 3\)

Step Operation Calculation Equation Progress
1 Innermost Parentheses \(24 - 12 - 4 = 8\)
\(20 - 4 = 16\)
\(4 + \frac{1}{6} \times [\{ -12 \times 8 \} \div 16]\)
2 Curly Braces \(-12 \times 8 = -96\) \(4 + \frac{1}{6} \times [-96 \div 16]\)
3 Square Brackets \(-96 \div 16 = -6\) \(4 + \frac{1}{6} \times [-6]\)
4 Multiplication \(\frac{1}{6} \times -6 = -1\) \(4 + (-1)\)
5 Addition \(4 + (-1) = 3\) \(3\)

Revision Table: Solving Equations with BODMAS

Concept Description Importance
BODMAS/PEMDAS Rule for the order of operations: Brackets/Parentheses, Orders/Exponents, Division/Multiplication, Addition/Subtraction. Ensures consistent and correct evaluation of mathematical expressions.
Simplification Reducing a mathematical expression to its simplest form. Makes calculations easier and leads to the final answer.
Innermost Brackets Calculations within the innermost grouping symbols (parentheses, braces, brackets) are done first. Crucial first step in complex expressions.

Additional Information: Importance of Order of Operations

The order of operations is fundamental in mathematics. Without a standard order, a single expression could be interpreted in multiple ways, leading to different results. For example, \(2 + 3 \times 4\). If you perform addition first (\(2+3=5\), then \(5 \times 4 = 20\)), you get 20. If you perform multiplication first (\(3 \times 4 = 12\), then \(2 + 12 = 14\)), you get 14. BODMAS/PEMDAS tells us multiplication comes before addition, so 14 is the correct answer. Following this order is essential for solving equations and expressions accurately, whether in basic arithmetic, algebra, or more advanced mathematics.

Mastering the application of BODMAS/PEMDAS to expressions involving fractions, negative numbers, and multiple layers of brackets is key to success in solving such problems.

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Similar Questions

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    -4 - (-7 - 12 ÷ 4) = ?

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  3. If A = (-14 + 4) and B = 4 - 14, then AB = ?

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  9. Find the value of the given expression.

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Important Questions from Bodmas Rule

  1. If 2945 ÷ 19 – 11 × 5 = 29 + a, find the value of a.

  2. DIRECTIONS: What should come in place of the question mark (?) in the following question?

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

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