Correct Answer: ÷, ×, +, =, ×, –

Solution : Given:
72 @ 9 @ 3 @ 6 @ 6 @ 6 @ 6

Replace the @ signs with the assigned mathematical signs in the options one by one –
First option: ÷, ×, +, =, –, +
72 ÷ 9 × 3 + 6 = 6 – 6 + 6
L.H.S.→ 72 ÷ 9 × 3 + 6
= 8 × 3 + 6
= 24 + 6 = 30
R.H.S.→ 6 – 6 + 6
= 6 – 12 = –6
L.H.S. ≠ R.H.S.
Second option: ÷, ×, +, =, ×, –
72 ÷ 9 × 3 + 6 = 6 × 6 – 6
L.H.S. →72 ÷ 9 × 3 + 6
= 8 × 3 + 6
= 24 + 6 = 30
R.H.S.→ 6 × 6 – 6
= 36 – 6 = 30
L.H.S. = R.H.S.
Third option: ×, ÷, =, –, +, ×
72 ÷ 9 × 3 = 6 – 6 + 6 × 6
L.H.S. →72 ÷ 9 × 3
= 8 × 3 = 24
R.H.S.→ 6 – 6 + 6 × 6
= 6 – 6 + 36
= 42 – 6 = 36
L.H.S. ≠ R.H.S.
Fourth option: +, ×, =, –, ÷, +
72 + 9 × 3 = 6 – 6 ÷ 6 + 6
L.H.S. →72 + 9 × 3
= 72 + 27 = 99
R.H.S. →6 – 6 ÷ 6 + 6
= 6 – 1 + 6
= 12 – 1 = 11
L.H.S. ≠ R.H.S.

So, only the second option satisfies the equation. Hence, the second option is correct.