Correct Answer: ×, –, +, ÷, =

Solution : Given:
15 * 5 * 24 * 140 * 7 * 71

Let's check the options –
First option: ÷, +, –, ×, =
15 ÷ 5 + 24 – 140 × 7 = 71
On solving the L.H.S. of the given equation –
= 15 ÷ 5 + 24 – 140 × 7
= 3 + 24 – 140 × 7
= 3 + 24 – 980
= –953 ≠ 71
Second option: ×, –, ÷, +, =
15 × 5 – 24 ÷ 140 + 7 = 71
On solving the L.H.S. of the given equation –
= 15 × 5 – 24 ÷ 140 + 7
= 15 × 5 – 0.171 + 7
= 75 – 0.171 + 7
= 81.829 ≠ 71
Third option: ×, –, +, ÷, =
15 × 5 – 24 + 140 ÷ 7 = 71
On solving the L.H.S. of the given equation –
= 15 × 5 – 24 + 140 ÷ 7
= 15 × 5 – 24 + 20
= 75 – 24 + 20
= 71
Fourth option: ×, ÷, +, –, =
15 × 5 ÷ 24 + 140 – 7 = 71
On solving the L.H.S. of the given equation –
= 15 × 5 ÷ 24 + 140 – 7
= 15 × 0.208 + 140 – 7
= 3.12 + 140 – 7
= 136.12 ≠ 71

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