The correct interchange of numbers is 6 and 2.
Using the BODMAS rule (Brackets, Orders, Division, Multiplication, Addition, Subtraction):
Interchange 6 and 2 in the original equation:
$2 \times 40 \div 8 + 6 - 5 = 11$
Step 1: Division ($\div$)
Divide 40 by 8:
$40 \div 8 = 5$
The equation becomes:
$2 \times 5 + 6 - 5 = 11$
Step 2: Multiplication ($\times$)
Multiply 2 by 5:
$2 \times 5 = 10$
The equation becomes:
$10 + 6 - 5 = 11$
Step 3: Addition ($+$)
Add 10 and 6:
$10 + 6 = 16$
The equation becomes:
$16 - 5 = 11$
Step 4: Subtraction ($-$)
Subtract 5 from 16:
$16 - 5 = 11$
Since $11 = 11$, the Left Hand Side (LHS) equals the Right Hand Side (RHS), making the equation correct.