IIMs Admission Criteria
CAT Daily Target
whatsapp
Join Coachify CAT Club
coachify logo
Formula PDF

Question 10.

The total of male and female populations in a city increased by 25% from 1970 to 1980. During the same period, the male population increased by 40% while the female population increased by 20%. From 1980 to 1990, the female population increased by 25%. In 1990, if the female population is twice the male population, then the percentage increase in the total of male and female populations in the city from 1970 to 1990 is

A
B
C
D
Previous Question
Rate this Solution★★★★★
Next Question

You have read 5 explanations without login

Text Explanation

Let us solve this question by assuming values(multiples of 100) and not variables(x).

Since we know that the female population was twice the male population in 1990, let us assume their respective values as 200 and 100.

Note that while assuming numbers, some of the population values might come out as a fraction(which is not possible, since the population needs to be a natural number). However, this would not affect our answer, since the calculations are in ratios and percentages and not real values of the population in any given year.


Now, we know that the female population became 1.25 times itself in 1990 from what it was in 1980.

Hence, the female population in 1980 = 200/1.25 = 160

Also, the female population became 1.2 times itself in 1980 from what it was in 1970.

Hence, the female population in 1970 = 160/1.2 = 1600/12 = 400/3

Let the male population in 1970 be x. Hence, the male population in 1980 is 1.4x.


Now, the total population in 1980 = 1.25 times the total population in 1970.

Hence, 1.25 (x + 400/3) = 1.4x + 160

Hence, x = 400/9.

Population change = 300 - 400/9 - 400/3 = 300 - 1600/9 = 1100/9

percentage change = $\frac{\frac{1100}{9}}{\frac{1600}{9}} \times 100 = \frac{1100}{16}\% = 68.75\%$

Video Explanation

Master CAT Preparation with Previous Year Papers

Practicing CAT previous year papers is one of the most effective strategies for CAT exam preparation. By solving questions from CAT 2021 quant-slot-3 and other previous years, you can understand the exam pattern, difficulty level, and types of questions asked in the Common Admission Test.

Why Practice CAT Previous Year Questions?

  • Understand Exam Pattern: CAT previous papers help you familiarize yourself with the question format, marking scheme, and time management required for the actual exam.
  • Identify Important Topics: By analyzing CAT solved questions from multiple years, you can identify frequently asked topics and focus your preparation accordingly.
  • Improve Speed and Accuracy: Regular practice of CAT previous year papers enhances your problem-solving speed and accuracy, which are crucial for scoring well in the exam.
  • Build Confidence: Solving CAT previous year questions builds confidence and reduces exam anxiety by making you comfortable with the exam format.

How to Use CAT Previous Papers Effectively

  1. Solve Under Exam Conditions: Attempt CAT previous year papers in a timed environment to simulate the actual exam experience.
  2. Analyze Your Performance: After solving each CAT previous paper, analyze your mistakes and identify areas that need improvement.
  3. Review Solutions Thoroughly: Study the detailed solutions and explanations provided for each question to understand the correct approach and methodology.
  4. Focus on Weak Areas: Use CAT solved questions to identify your weak areas and dedicate more time to improving them.

CAT Exam Sections Covered

Our comprehensive collection of CAT previous papers covers all three sections of the exam:

  • VARC (Verbal Ability & Reading Comprehension): Practice reading comprehension passages, para jumbles, and other verbal ability questions from CAT previous years.
  • DILR (Data Interpretation & Logical Reasoning): Master DI and LR questions with detailed solutions from CAT previous year papers.
  • QA (Quantitative Ability): Solve arithmetic, algebra, geometry, and other quantitative ability questions from CAT solved papers.

Additional CAT Preparation Resources

Looking for more CAT preparation materials? Explore our comprehensive collection of:

Note: Regular practice of CAT previous year papers, combined with a structured study plan, is essential for achieving a high percentile in the CAT exam. Make sure to solve questions from all sections and review the solutions thoroughly to maximize your preparation effectiveness.

Quant Essentials
Quant Essentials