720 ÷ 12 + 18 × 4 ÷ 6 + 25% of 160 = ?

Question

720 ÷ 12 + 18 × 4 ÷ 6 + 25% of 160 = ?

1. A. 88
2. B. 66
3. C. 62 (Correct answer)
4. D. 72

Correct Answer

Option C — 62

Detailed Solution & Explanation

The correct answer is 62.

Key Points

• Apply BODMAS — Brackets, Orders, Division, Multiplication, Addition, Subtraction.
• $\{720 \div 12 + 18 \times 4\} \div 6 + 25\% \text{ of } 160$
• Inside the brackets, division and multiplication come before addition:
  • $720 \div 12 = 60, \qquad 18 \times 4 = 72$
  • $\{60 + 72\} = 132$
• Then the outer division:
  • $132 \div 6 = 22$
• Then the percentage term:
  • $25\% \text{ of } 160 = \frac{160}{4} = 40$
• Finally the addition:
  • $22 + 40 = \mathbf{62}$

Shortcut Trick

• Convert percentages to fractions before multiplying: 25% = 1/4, so $25\%$ of $160$ is just $160 \div 4 = 40$. Useful conversions: $12.5\% = \frac{1}{8}$, $20\% = \frac{1}{5}$, $33\frac{1}{3}\% = \frac{1}{3}$, $37.5\% = \frac{3}{8}$.

Additional Information

• The commonest error is dividing 720 by 12 and then by 6 in one sweep, or adding before multiplying inside the bracket. Work strictly innermost-outward and write each intermediate value down.
• The word "of" always means multiplication, and it binds at the same level as multiplication in the BODMAS order.