Correct Answer: 3 and 9

Solution : Given:
8 × 4 – 3 + 57 ÷ 9 = 42

Replace the given numbers according to the options one by one with the original numbers in the given equation.
First option: 8 and 4
⇒ 4 × 8 – 3 + 57 ÷ 9 = 42
Solving the L.H.S. of the equation –
= 4 × 8 – 3 + 6.34
= 32 – 3 + 6.34
= 35.34 ≠ 42
Second option: 3 and 9
⇒ 8 × 4 – 9 + 57 ÷ 3 = 42
Solving the L.H.S. of the equation –
= 8 × 4 – 9 + 19
= 32 – 9 + 19
= 42 = R.H.S.
Third option: 57 and 9
⇒ 8 × 4 – 3 + 9 ÷ 57 = 42
Solving the L.H.S. of the equation –
= 8 × 4 – 3 + 0.16
= 32 – 3 + 0.16
= 29.16 ≠ 42
Fourth option: 42 and 57
⇒ 8 × 4 – 3 + 42 ÷ 9 = 57
Solving the L.H.S. of the equation –
= 8 × 4 – 3 + 4.67
= 32 – 3 + 4.67
= 33.67 ≠ 57

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