Correct Answer: 15 + 5 ÷ 1 – 9 × 4 = 70

Solution : Let's check the options –
First option: 15 + 5 ÷ 1 – 9 × 4 = 70
On interchanging the mathematical signs, we get –
⇒ 15 + 5 ÷ 1 × 9 – 4 = 70
Solving the L.H.S. of the equation –
= 15 + 5 × 9 – 4
= 15 + 45 – 4
= 60 – 4
= 56
≠ 70
Second option: 5 – 6 × 3 + 16 ÷ 4 = 31
On interchanging the mathematical signs, we get –
⇒ 5 × 6 – 3 + 16 ÷ 4 = 31
Solving the L.H.S. of the equation –
= 5 × 6 – 3 + 4
= 30 – 3 + 4
= 34 – 3
= 31
Third option: 11 + 6 × 3 – 8 ÷ 2 = 5
On interchanging the mathematical signs, we get –
⇒ 11 + 6 – 3 × 8 ÷ 2 = 5
Solving the L.H.S. of the equation –
= 11 + 6 – 3 × 4
= 11 + 6 – 12
= 17 – 12
= 5
Fourth option: 15 – 4 × 3 + 6 ÷ 1 = 63
On interchanging the mathematical signs, we get –
⇒ 15 × 4 – 3 + 6 ÷ 1 = 63
Solving the L.H.S. of the equation –
= 15 × 4 – 3 + 6
= 60 – 3 + 6
= 66 – 3
= 63

So, only the first option does not satisfy the given equation. Hence, the first option is correct.