Correct Answer: 6 and 4

Solution : Given:
3 × 9 – 4 ÷ 2 + 6 = 28

Replace the given numbers according to the options one by one with the original numbers in the given equation.
First option: 9 and 2
= 3 × 2 – 4 ÷ 9 + 6
= 6 – 0.45 + 6
= 11.56 ≠ 28
Second option: 6 and 4
= 3 × 9 – 6 ÷ 2 + 4
= 27 – 3 + 4
= 28
Third option: 3 and 6
= 6 × 9 – 4 ÷ 2 + 3
= 54 – 2 + 3
= 55 ≠ 28
Fourth option: 9 and 6
= 3 × 6 – 4 ÷ 2 + 9
= 18 – 2 + 9
= 25 ≠ 28

Here, only the second option satisfies the R.H.S. of the given equation. Hence, the second option is correct.