What will come in the place of the question mark (?) in the following equation, if ‘+’ and ‘−’ are interchanged and ‘×’ and ‘÷’ are interchanged? 101 ÷ 48 − 13013 × 13 + 12 = ?

Correct — C.
Rule: swap the symbols on the printed line first, then apply BODMAS to the new line.

With + and − interchanged and × and ÷ interchanged, 101 ÷ 48 − 13013 × 13 + 12 becomes
101 × 48 + 13013 ÷ 13 − 12

Divide: 13013 ÷ 13 = 1001
Multiply: 101 × 48 = 4848
Add: 4848 + 1001 = 5849
Subtract: 5849 − 12 = 5837

That is option (c).

Why the others are wrong

• (a)
  5834 — 5834 is three below the total. It needs 4845 where the line has 101 × 48, and that product is 4848.
• (b)
  5836 — 5836 needs 13 taken off at the end. The swap turns the trailing + 12 into − 12, so 12 is what comes off, not 13.
• (d)
  5835 — 5835 follows from reading 13013 ÷ 13 as 999 instead of 1001, since 4848 + 999 − 12 = 5835.

Symbol-interchange items test two things in sequence and candidates lose marks on the first.

Step one is mechanical: rewrite the equation with every named symbol replaced. Step two is ordinary BODMAS on the rewritten line — division and multiplication before addition and subtraction, left to right within each rank.

The arithmetic is then deliberately heavy, so the numbers are chosen to have clean factorisations. 13013 = 13 × 1001 and 101 × 48 = 4848 both fall out quickly once you look for them.

Key facts

• The interchange applies to the printed line first, and BODMAS runs on the result.
• 13013 ÷ 13 = 1001, because 13013 = 13 × 1001.
• 101 × 48 = 4848.

Common traps

• Evaluating the printed line and swapping the answer afterwards
• Applying only one of the two named swaps

No directly related past PYQ was found.