By Interchanging the given two numbers which of the following equations will be NOT correct?
1 and 9
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 9 - 1 + 7 = -3.
Option 1: 9 × 2 - 1 + 8 = 9
After interchanging numbers equation becomes;
⇒ (1 × 2) - 9 + 8 = 1
⇒ 2 - 9 + 8 = 1
⇒ 10 - 9 = 1
⇒ 1 = 1
Option 2: 9 × 2 + 1 - 4 = 7
After interchanging numbers equation becomes;
⇒ (1 × 2) + 9 - 4 = 7
⇒ (2 + 9) - 4 = 7
⇒ 11 - 4 = 7
⇒ 7 = 7
Option 3: 9 - 1 + 7 = - 3
After interchanging numbers equation becomes;
⇒ 1 - 9 + 7 = - 3
⇒ 8 - 9 = - 3
⇒ - 1 ≠ - 3
Option 4: 1 + 9 × 3 - 4 = 8
⇒ 9 + (1 × 3) - 4 = 8
⇒ 9 + 3 - 4 = 8
⇒ 12 - 4 = 8
⇒ 8 = 8
Hence, the equation of option 3 will be not correct.