By Interchanging the given two numbers which of the following equation will be not correct?
1 and 9
Analyze Equation Validity After Interchanging 1 and 9
The question asks to identify which equation becomes incorrect when the digits 1 and 9 are swapped.
Step 1: Interchange Digits in Each Option
We will replace every '1' with '9' and every '9' with '1' in each given equation.
Step 2: Evaluate Each Modified Equation
Option 1: Original Equation $9 \times 2 - 1 + 8 = 1$
After interchanging 1 and 9, the equation becomes:
Evaluating the expression:
The result is $1$, which matches the right side ($1 = 1$). This equation remains correct.
Option 2: Original Equation $9 \times 2 + 1 - 4 = 7$
After interchanging 1 and 9, the equation becomes:
Evaluating the expression:
The result is $7$, which matches the right side ($7 = 7$). This equation remains correct.
Option 3: Original Equation $9 - 1 + 7 = -3$
After interchanging 1 and 9, the equation becomes:
Evaluating the expression:
The result is $-1$. The right side is $-3$. Since $-1 \neq -3$, this equation becomes incorrect.
Option 4: Original Equation $1 + 9 \times 3 - 4 = 8$
After interchanging 1 and 9, the equation becomes:
Evaluating the expression (following order of operations):
The result is $8$, which matches the right side ($8 = 8$). This equation remains correct.
Conclusion
The equation that becomes incorrect after interchanging the numbers 1 and 9 is Option 3 ($1 - 9 + 7 = -1$, which does not equal $-3$).
Important Questions from Mathematical Operations
Select the set, from the given options, in which the numbers are related in the same way as are the numbers of the following sets.
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
(6, 13, 78)
(5, 22, 110)
If + means -, - means ×, × means ÷, ÷ means +, then what will come in place of the question mark (?) in the following equation?
28 - 6 ÷ 4 + 14 × 14 = ?
In the following number-pairs, the second number is obtained by applying certain mathematical operations to the first number. Which numbers should replace X and Y so that the pattern followed by the two numbers on the left side of :: is the same as that on the right side of :: ?
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g. 13 Operations on 13 such as adding/subtracting /multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
X : 649 :: 956 : Y
Which two numbers should be interchanged to make the given equation correct?
75 ÷ 5 + 15 × 4 - 17 × 3 + (60 ÷ 6) × 10 = 100
(Note: Interchange should be done of the entire number and not individual digits of a given number.)
If '+' means minus, '-' means multiplication, '÷' means plus, and 'x' means division, then solve the equation:
15 - 3 + 10 x 5 ÷ 5
