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Question

After interchanging the given two numbers (Not digits) what will be the values of expression (I) and (II) respectively ?

4 and 6

I. 8 – 4 × 3 + 6 ÷ 2

II. 4 + 3 × 6 – 8 ÷ 2

The correct answer is

–8 and 14

Evaluating Expressions After Number Interchange

The problem asks us to interchange the given two numbers, 4 and 6, in two different mathematical expressions and then evaluate the resulting expressions. We need to find the new values of Expression (I) and Expression (II) respectively after performing the interchange.

Step 1: Understanding the Number Interchange

We are given two numbers: 4 and 6. The instruction is to interchange these numbers. This means wherever the number 4 appears in the original expressions, we will replace it with 6, and wherever the number 6 appears, we will replace it with 4. We will then evaluate the new expressions using the standard order of operations (BODMAS/PEMDAS).

Step 2: Evaluating Expression (I) After Interchange

The original Expression (I) is: $8 – 4 × 3 + 6 ÷ 2$

After interchanging 4 and 6, the new Expression (I) becomes:

$8 – \mathbf{6} × 3 + \mathbf{4} ÷ 2$

Now, let's evaluate this new expression using the order of operations (Division and Multiplication first, then Addition and Subtraction from left to right).

  • First, perform the division: $4 ÷ 2 = 2$
  • The expression is now: $8 – 6 × 3 + 2$
  • Next, perform the multiplication: $6 × 3 = 18$
  • The expression is now: $8 – 18 + 2$
  • Finally, perform addition and subtraction from left to right: $8 – 18 = -10$
  • Then: $-10 + 2 = -8$

So, the value of Expression (I) after interchanging the numbers is -8.

Step 3: Evaluating Expression (II) After Interchange

The original Expression (II) is: $4 + 3 × 6 – 8 ÷ 2$

After interchanging 4 and 6, the new Expression (II) becomes:

$\mathbf{6} + 3 × \mathbf{4} – 8 ÷ 2$

Now, let's evaluate this new expression using the order of operations.

  • First, perform the division: $8 ÷ 2 = 4$
  • The expression is now: $6 + 3 × 4 – 4$
  • Next, perform the multiplication: $3 × 4 = 12$
  • The expression is now: $6 + 12 – 4$
  • Finally, perform addition and subtraction from left to right: $6 + 12 = 18$
  • Then: $18 – 4 = 14$

So, the value of Expression (II) after interchanging the numbers is 14.

Conclusion

After interchanging the numbers 4 and 6, the value of Expression (I) is -8 and the value of Expression (II) is 14. The values of the expressions are -8 and 14 respectively.

Revision Table: Expression Evaluation

Expression Original After Interchanging 4 and 6 Evaluation Steps (After Interchange) Final Value
Expression (I) $8 – 4 × 3 + 6 ÷ 2$ $8 – 6 × 3 + 4 ÷ 2$ $8 – 18 + 2 = -10 + 2$ -8
Expression (II) $4 + 3 × 6 – 8 ÷ 2$ $6 + 3 × 4 – 8 ÷ 2$ $6 + 12 – 4 = 18 – 4$ 14

Additional Information: Order of Operations

When evaluating mathematical expressions involving multiple operations, we follow a specific order to ensure a consistent result. This order is commonly known as BODMAS or PEMDAS.

  • BODMAS: Brackets, Orders (powers/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 this problem, we used Division and Multiplication before Addition and Subtraction. When operations of the same priority level (like Division and Multiplication, or Addition and Subtraction) appear, we perform them from left to right in the expression.

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Important Questions from Logical Puzzle

  1. Seven persons P, Q, R, S, T, U and V like different watches namely W1, W2, W3, W4, W5, W6 and W7 (not necessarily in the same order). P and R do not like odd numbered watch. T likes W5. U does not like W2 or W3 or W6 or W7. P likes prime numbered watch. Q likes W4. S likes W2 or W7. Which of the following statement(s) is/are correct ?

    I. S likes W7.

    II. R likes W2.

    III. U likes W1.

    IV. V likes W3.

  2. If ‘+’ means ‘×’, ‘×’ means ‘÷’, ‘÷’ means ‘–’ and ‘–’ means ‘+’, then

    16 + 18 × 3 ÷ 6 = ?

  3. In a certain code language, ‘Today is last match’ is written as ‘Sa Te Mo Pt’, ‘Last king like your team’ is written as ‘De Ra Mo Lo Zs’, ‘Our team won today match’ is written as ‘Te Ra Pt Ae We’. What is the code for ‘Our won is Last’ in that code language?

  4. In a certain code language, ‘LETTER’ is written as ‘ZLZYIO’. What is the code for ‘ACTION’ in that code language?

  5. If A denotes ‘+’, B denotes ‘×’, C denotes ‘-’, and D denotes ‘÷’, then what will come in place of ‘?’ in the following equation?

    34 A 15 B 3 C 11 B 2 A (51 D 17) = ?

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