Correct Answer: – and +

Solution : Given:
(45 × 2) ÷ 15 – (6 × 3) + 10 – (63 ÷ 21) = 17

Replace the given symbols in the options one by one with the original symbols in the given equation.
First option: ÷ and +;
⇒(45 × 2) + 15 – (6 × 3) ÷ 10 – (63 + 21) = 17
90 + 15 – 18 ÷ 10 – 84 = 17
90 + 15 – 1.8 – 84 = 17
19.2 ≠ 17
Second option: × and –;
⇒(45 – 2) ÷ 15 × (6 – 3) + 10 × (63 ÷ 21) = 17
43 ÷ 15 × 3 + 10 × 3 = 17
2.86 × 3 + 10 × 3 = 17
8.6 + 30 = 17
38.6 ≠ 17
Third option: – and +;
⇒(45 × 2) ÷ 15 + (6 × 3) – 10 + (63 ÷ 21) = 17
90 ÷ 15 + 18 – 10 + 3 = 17
6 + 18 – 10 + 3 = 17
17 = 17
Fourth option: ÷ and ×
⇒(45 ÷ 2) × 15 – (6 ÷ 3) + 10 – (63 × 21) = 17
22.5 × 15 – 2 + 10 – 1323 = 17
337.5 – 2 + 10 – 1323 = 17
–977.5 ≠ 17

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