Practice Questions
Concept Explanation
Population problems apply percentage increase/decrease to a base count. Always identify whether the change is on the original population or on a new value after prior change.
Increase and Decrease
New population = Original × (1 ± P/100).
Net Change Over Two Periods
Multiply successive multipliers. Example: +20% then −10% → 1.2 × 0.9 = 1.08 → net +8%.
Men and Women Split
If males are 55% of population, females are 45%. Use part-whole percentage relations carefully.
-
Q1 Easy
A town has a population of 20,000. It increases by 15%. What is the new population?
ExplanationIncrease = 3,000. New population = 23,000. -
Q2 Easy
The population of a village decreases from 12,000 to 10,800. What is the percentage decrease?
ExplanationDecrease = 1,200. Percentage = (1,200/12,000) × 100 = 10%. -
Q3 Easy
In a city of 50,000 people, 60% are literate. How many are literate?
Explanation60% of 50,000 = 30,000. -
Q4 Medium
A population of 80,000 grows by 10% in the first year and 5% in the second year. The population after two years is:
ExplanationFinal = 80,000 × 1.1 × 1.05 = 92,400. -
Q5 Medium
In a colony, 45% of residents are children. If there are 1,800 children, what is the total population?
Explanation45% of total = 1,800 → total = 1,800 × (100/45) = 4,000. -
Q6 Medium
The population of a town was 25,000. It increased by 12% and then decreased by 8%. The final population is:
ExplanationFinal = 25,000 × 1.12 × 0.92 = 25,760. -
Q7 Easy
In a survey, 35% of 4,000 respondents preferred product A. How many preferred product A?
Explanation35% of 4,000 = 1,400.
-
Q8 Medium
A city's population is 1,20,000. If males are 52% of the population, how many females are there?
ExplanationFemales = 48% of 1,20,000 = 57,600. -
Q9 Easy
The population of a town decreases by 20% every decade. From 1,00,000, what is it after one decade?
ExplanationNew = 1,00,000 × 0.8 = 80,000. -
Q10 Medium
A village population rises from 8,000 to 9,200. The percentage increase is:
ExplanationIncrease = 1,200. Percentage = (1,200/8,000) × 100 = 15%. -
Q11 Easy
In a town, 70% of adults are employed. If the adult population is 35,000, how many are employed?
Explanation70% of 35,000 = 24,500. -
Q12 Hard
A population increases by 25% and then by 20%. The net percentage increase is:
ExplanationNet multiplier = 1.25 × 1.2 = 1.5 → 50% increase. -
Q13 Hard
After a 15% increase, a town has 46,000 people. What was the original population?
ExplanationOriginal = 46,000/1.15 = 40,000. -
Q14 Medium
In a district, urban population is 30% of total 2,50,000. Rural population is:
ExplanationRural = 70% of 2,50,000 = 1,75,000.
-
DS1 Easy
What is the new population?
Statement IThe original population is 20,000.
Statement IIIt increases by 15%.
ExplanationNew = 20,000 × 1.15 = 23,000. Both statements needed. -
DS2 Medium
What is the total population?
Statement I45% of the population are children.
Statement IIThere are 1,800 children.
ExplanationTotal = 1,800 × (100/45) = 4,000. Both needed.
-
DS3 Medium
What is the population after two years?
Statement IInitial population is 80,000.
Statement IIIt grows 10% in year 1 and 5% in year 2.
ExplanationFinal = 80,000 × 1.1 × 1.05 = 92,400. -
DS4 Easy
Is the population more than 25,000?
Statement IAfter a 12% increase then 8% decrease starting from 25,000, the final count is 25,760.
Statement IIThe original population was 25,000.
ExplanationStatement I gives the final count 25,760 directly, which is greater than 25,000.