By interchanging the given two numbers (not digits) which of the following equation will NOT be correct? 3 and 7
I. 7 × 9 + 3 - 8 ÷ 2 = 30
II. 2 × 3 + 7 - 4 ÷ 1 = 13
Show answer & explanation
Correct answer: D
Explanation
Interchanging the numbers 3 and 7 in both equations:
I. 7 × 9 + 3 − 8 ÷ 2 = 30
3 × 9 + 7 − 8 ÷ 2 = 30
3 × 9 + 7 − 4 = 30
27 + 7 − 4 = 30
34 - 4 = 30
30 = 30 (The equation is correct)
II. 2 × 3 + 7 − 4 ÷ 1 = 13
2 × 7 + 3 − 4 ÷ 1 = 13
2 × 7 + 3 − 4 = 13
14 + 3 − 4 = 13
17 − 4 = 13
13 = 13 (The equation is correct)
Option 4 is the correct answer, neither I nor II