Correct Answer: 6 + 20 ÷ 12 × 7 – 11 = 70

Solution : Given:
Interchange the signs + and ÷

Replace the given signs in the options one by one with the original signs in the given equation.
First option: 12 ÷ 8 × 12 + 6 – 7 = 21
⇒ 12 + 8 × 12 ÷ 6 – 7
= 12 + 16 – 7
= 21
Second option: 9 – 3 + 12 × 8 ÷ 4 = 11
⇒ 9 – 3 ÷ 12 × 8 + 4
= 9 – 2 + 4
= 11
Third option: 46 + 23 ÷ 14 × 5 – 6 = 66
⇒ 46 ÷ 23 + 14 × 5 – 6
= 2 + 70 – 6
= 66
Fourth option: 6 + 20 ÷ 12 × 7 – 11 = 70
⇒ 6 ÷ 20 + 12 × 7 – 11
= 0.3 + 84 – 11
= 73.3 ≠ 70

So, only the fourth option satisfies the L.H.S. ≠ R.H.S. of the given equation. Hence, the fourth option is correct.