Correct Answer: 5 × 2 – 8 + 9 ÷ 1 = 20

Solution : Given:
Interchange the numbers 5 and 8.

Replace the given numbers in the options with the original numbers in the given equation.
First option: 5 × 2 – 8 + 9 ÷ 1 = 20
⇒ 8 × 2 – 5 + 9 ÷ 1
= 16 – 5 + 9
= 20
Second option: 8 + 5 × 4 – 9 ÷ 3 = 30
⇒ 5 + 8 × 4 – 9 ÷ 3
= 5 + 32 – 3
= 34 ≠ 30
Third option: 5 × 7 + 8 – 3 ÷ 1 = 55
⇒ 8 × 7 + 5 – 3 ÷ 1
= 56 + 5 – 3
= 58 ≠ 55
Fourth option: 8 – 5 × 2 + 6 ÷ 2 = –9
⇒ 5 – 8 × 2 + 6 ÷ 2
= 5 – 16 + 3
= –8 ≠ –9

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