The population of a village decreased from 1,230 to 1,040 due to breakout of an epidemic. What is the percentage decrease in the population?

Step 1: Analyze the question We need the percentage decrease when the population falls from 1,230 to 1,040.

Step 2: The concept Percentage decrease = (Decrease ÷ Original value) × 100%

Step 3: Solve

Decrease = 1,230 − 1,040 = 190

Percentage decrease = (190 ÷ 1,230) × 100%

190 ÷ 1,230 = 19/123 ≈ 0.154471...

Let's check by long division:

• 123 × 0.15 = 18.45, remainder 19 − 18.45 = 0.55
• 0.55 ÷ 123 ≈ 0.004472
• So 19/123 ≈ 0.154472

Percentage decrease ≈ 15.4472%

Step 4: Round and match the options

• To 2 decimal places: 15.4472% ≈ 15.45%
• Option A (15.44%) would need the value to be truncated rather than rounded.
• Options B and C (15.43%, 15.42%) are too low.

45%).

Step 5: Exam tip Always divide by the original value (the starting figure), not the new one. If you divided by 1,040 you would get 18.27%, a common trap. Also, when options are very close together, carry your division to at least 3 or 4 decimal places before rounding so you don't pick a wrongly rounded value.