If '+' means '−', '−' means '×', '×' means '÷' and '÷' means '+', then what…
2025
If '+' means '−', '−' means '×', '×' means '÷' and '÷' means '+', then what will come in place of the question mark (?) in the following equation?
36 ÷ 320 × 5 + 12 − 6 = ?
- A.
28
- B.
24
- C.
26
- D.
27
Attempted by 4 students.
Show answer & explanation
Correct answer: A
Concept: In symbol-substitution puzzles, first replace every arithmetic sign in the given equation with the sign it is stated to ‘mean’, then evaluate the resulting expression using the standard order of operations (BODMAS): multiplication and division are carried out before addition and subtraction, working left to right within each precedence level.
The stated code is: '+' means '−', '−' means '×', '×' means '÷', and '÷' means '+'.
Rewrite 36 ÷ 320 × 5 + 12 − 6 by replacing each sign with its meaning (÷→+, ×→÷, +→−, −→×): 36 + 320 ÷ 5 − 12 × 6.
Apply BODMAS to the division and multiplication terms first: 320 ÷ 5 = 64 and 12 × 6 = 72.
Substitute these results back into the expression: 36 + 64 − 72.
Compute left to right: 36 + 64 = 100, and 100 − 72 = 28.
Cross-check: Re-checking the code mapping against the original statement confirms each substitution (÷→+, ×→÷, +→−, −→×) was applied correctly, and regrouping the same three quantities in a different order, (36 − 72) + 64 = −36 + 64 = 28, reproduces the identical result.