Which of the given equations becomes correct if the signs '+' and '×' are swapped?

To determine which equation becomes correct when the signs '+' and '×' are swapped, we need to replace every '+' with '×' and every '×' with '+' in each given option, and then evaluate the expression using the standard BODMAS/PEMDAS order of operations (Operations inside parentheses, Division and Multiplication from left to right, Addition and Subtraction from left to right).

The correct option provided is 8 × 4 + 5 = 28.

Let's check and verify each option step-by-step:

1. First Option: 7 × 2 + 3 = 20

Swapping '+' and '×' gives the new equation:

$7+2\times 3$

Perform multiplication first:

$2\times 3=6$

Now perform addition:

$7+6=13$

Since 13 ≠ 20, this equation is incorrect.

2. Second Option (Correct Option): 8 × 4 + 5 = 28

Swapping '+' and '×' gives the new equation:

$8+4\times 5$

Perform multiplication first:

$4\times 5=20$

Now perform addition:

$8+20=28$

Since 28 = 28, this equation becomes correct after swapping the signs.

3. Third Option: 5 + 4 × 6 = 54

Swapping '+' and '×' gives the new equation:

$5\times 4+6$

Perform multiplication first:

$5\times 4=20$

Now perform addition:

$20+6=26$

Since 26 ≠ 54, this equation is incorrect.

4. Fourth Option: 4 + 6 × 2 = 20

Swapping '+' and '×' gives the new equation:

$4\times 6+2$

Perform multiplication first:

$4\times 6=24$

Now perform addition:

$24+2=26$

Since 26 ≠ 20, this equation is incorrect.

Therefore, the equation that becomes correct after interchanging '+' and '×' is 8 × 4 + 5 = 28.