Evaluate: 80% of 350 − 37 (1⁄2) % of 160 + 11% of 500

Correct — C. Work out each percentage, then combine left to right.

80% of 350 = 0.8 × 350 = 280
37½% of 160 = 3⁄8 × 160 = 60
11% of 500 = 0.11 × 500 = 55

Subtract: 280 − 60 = 220
Add: 220 + 55 = 275 → option (c)

Why the others are wrong

• (a)
  225 — 225 would need 37½% of 160 to be 110. It is 160 ÷ 8 × 3 = 60, so the total is 280 − 60 + 55 = 275.
• (b)
  250 — 250 would need the middle term to be 85, but 37½% is 3⁄8, and 3⁄8 of 160 is 60. With 60 the sum comes to 275.
• (d)
  300 — 300 would need 11% of 500 to be 80. It is 5 × 11 = 55, so 280 − 60 + 55 lands on 275, 25 short of 300.

Percentages that are simple fractions make these sums fast: 12½% = 1⁄8, 37½% = 3⁄8, 62½% = 5⁄8, 87½% = 7⁄8.

So 37½% of 160 is 160 ÷ 8 × 3 = 60, with no decimals. The others are direct: 80% is 4⁄5 of 350, and 11% of 500 is 5 × 11.

Key facts

• 37½% = 3⁄8
• x% of y = y% of x, so 11% of 500 = 500% of 11 = 55.
• Addition and subtraction have equal priority and run left to right: 280 − 60 + 55 = 275.

Common traps

• Reading 37 (1⁄2) % as 37 × ½ per cent instead of 37½ per cent.
• Subtracting 60 and 55 together, 280 − (60 + 55) = 165, when the + belongs only to 55.

No directly related past PYQ was found.