Correct Answer: – and +

Solution : Given:
9 × 4 + 6 ÷ 3 – 5 = 39

On interchanging the symbols as given in the options, we get –
First option: ÷ and –
9 × 4 + 6 – 3 ÷ 5 = 39
Solving the L.H.S. of the equation –
= 9 × 4 + 6 – 0.6
= 36 + 6 – 0.6
= 41.4 ≠ 39
Second option: × and +
9 + 4 × 6 ÷ 3 – 5 = 39
Solving the L.H.S. of the equation –
= 9 + 4 × 2 – 5
= 9 + 8 – 5
= 12 ≠ 39
Third option: – and +
9 × 4 – 6 ÷ 3 + 5 = 39
Solving the L.H.S. of the equation –
= 9 × 4 – 2 + 5
= 36 – 2 + 5
= 39 = R.H.S.
Fourth option: – and =
9 × 4 + 6 ÷ 3 = 5 – 39
Solving the L.H.S. of the equation –
= 9 × 4 + 6 ÷ 3
= 9 × 4 + 2
= 36 + 2
= 38
R.H.S. = 5 – 39 = –34
38 ≠ –34

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