Question

If '+' means '$\div$', '$\div$' means '$-$', '$-$' means '$\times$' and '$\times$' means '$+$', then $10+5\div3-2\times9$ is equal to:

• A. 6
• B. 8
• C. 7
• D. 10
• E. 5

Hint:

Write the conversion table (e.g., $+\rightarrow\div$) on your scratch pad first to avoid mental slips during substitution.

Answer 1

Answer: (E)

Concept: Substitute the symbols first, then apply the BODMAS (Brackets, Orders, Division, Multiplication, Addition, Subtraction) rule.
Step 1: Rewrite the expression with new symbols.
Original: $10 + 5 \div 3 - 2 \times 9$ New: $10 \div 5 - 3 \times 2 + 9$

Step 2: Solve using BODMAS.
• Division: $10 \div 5 = 2$
• Multiplication: $3 \times 2 = 6$
• Expression becomes: $2 - 6 + 9$
• Addition/Subtraction: $2 + 9 - 6 = 11 - 6 = 5$.