Which two numbers and two signs should be interchanged in the following equation to make it correct?

18 - 6 + 11 × 5 + 18 = 113

Here, we use the BODMAS table  given below:

Given:

18 - 6 + 11 \(\times\) 5 + 18 = 113

(1) 6 and 5, + and \(\times\)

After interchanging the respective values and signs the equation becomes:

18 - 5 \(\times\) 11 + 6 + 18 = 113

After applying BODMAS rule,

18 - 55 + 6 + 18 

42 - 55 = -13

it doesn't satisfy the equation.

(2) 18 and 5, + and \(\times\)

After interchanging the respective values and signs the equation becomes:

5 - 6 + 11 + 18 \(\times\) 18 = 113

After applying BODMAS rule,

5 - 6 + 11 + 324

340 - 6 = 334

It doesn't satisfy the equation.

(3) 6 and 5, - and \(\times\)

After interchanging the respective values and signs the equation becomes:

18 \(\times\) 5 + 11 - 6 + 18 = 113

After applying BODMAS rule,

90 + 11 - 6 + 18

119 - 6 = 113

Here LHS = RHS, it satisfies the equation.

(4) 18 and 5, - and \(\times\)

After interchanging the respective values and signs the equation becomes:

5 \(\times\) 6 + 11 - 18 + 18 = 113

After applying BODMAS rule,

30 + 11 - 18 + 18

49 - 18 = 31

It doesn't satisfy the equation.

Hence the correct answer is Option 3.