Correct Answer: ÷ and ×

Solution : Given:
10 – 4 + 13 ÷ 15 × 3 = 71

Replace the signs given in the equation with the assigned signs in the options one by one –
First option: + and ×
⇒ 10 – 4 × 13 ÷ 15 + 3 = 71
Solving the L.H.S. of the equation –
= 10 – 4 × 0.87 + 3
= 10 – 3.48 + 3
= 13 – 3.48
= 9.52 ≠ 71
Second option: – and ÷
⇒ 10 ÷ 4 + 13 – 15 × 3 = 71
Solving the L.H.S. of the equation –
= 2.5 + 13 – 15 × 3
= 2.5 + 13 – 45
= 15.5 – 45
= –29.5 ≠ 71
Third option: ÷ and ×
⇒ 10 – 4 + 13 × 15 ÷ 3 = 71
Solving the L.H.S. of the equation –
= 10 – 4 + 13 × 5
= 10 – 4 + 65
= 75 – 4
= 71
Fourth option: – and ×
⇒ 10 × 4 + 13 ÷ 15 – 3 = 71
Solving the L.H.S. of the equation –
= 10 × 4 + 0.87 – 3
= 40 + 0.87 – 3
= 40.87 – 3
= 37.87 ≠ 71

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