Which number will come in the place of the question mark (?) in the following equation if ‘+’ and ‘−’ are interchanged and ‘×’ and ‘÷’ are interchanged?
20 + 10 × 2 − 4 ÷ 5 = ?

Question

Accepted Answer

Original expression: 20 + 10 × 2 − 4 ÷ 5

According to the problem, '+' and '−' are interchanged, and '×' and '÷' are interchanged.

So, replace:
'+' with '−'
'−' with '+'
'×' with '÷'
'÷' with '×'

The expression becomes:
20 − 10 ÷ 2 + 4 × 5

Now, follow the order of operations (BODMAS/BIDMAS):
1. Division and multiplication from left to right
2. Addition and subtraction from left to right

Calculate 10 ÷ 2 = 5
Calculate 4 × 5 = 20

Expression now: 20 − 5 + 20

Calculate from left to right:
20 − 5 = 15
15 + 20 = 35

Therefore, the result is 35.

However, the options given are 45, 30, 35, 40, but the explanation above yields 35.

Double-checking the calculation:
Expression after interchange: 20 − 10 ÷ 2 + 4 × 5
Calculate division and multiplication:
10 ÷ 2 = 5
4 × 5 = 20
Expression: 20 − 5 + 20
Calculate left to right:
20 − 5 = 15
15 + 20 = 35

So the correct answer is 35.

Answer

Answer

Answer