Mathematics/General Ability MCQs
Topic Notes: Mathematics/General Ability
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
121
In a zoo, 30% are monkeys, 40% are deer, and the remaining are bears. If there are 150 bears, total animals?
Answer:
500
Bears percentage = 100% - (30% + 40%) = 30%. 30% of total = 150. Total = 150 / 0.30 = 500.
122
Population of a town is 8000. If males increase by 6% and females by 10%, the population becomes 8600. Number of females?
Answer:
3800
M + F = 8000. New: 1.06M + 1.10F = 8600. Substitute M = 8000 - F: 1.06(8000 - F) + 1.10F = 8600 -> 848 + 0.04F = 8600 -> 0.04F = 152 -> F = 3800.
123
The population of a town was 160000. In 3 years it increased to 185220. The annual rate of increase is?
Answer:
5%
P = P0(1 + r/100)^3. 185220 = 160000(1 + r/100)^3. (1 + r/100)^3 = 185220 / 160000 = 9261 / 8000 = (21/20)^3. So 1 + r/100 = 1.05. r = 5%.
124
A tree's height increases by 10% annually. If its present height is 121 cm, what was its height 2 years ago?
Answer:
100 cm
Let original height be h. h * (1.10)^2 = 121. h * 1.21 = 121. h = 100 cm.
125
The population of a town increases from 60,000 to 65,000. What is the percentage increase?
Answer:
8.33%
Increase = 5000. Percentage increase = (Increase / Original) * 100 = (5000 / 60000) * 100 = 8.33%.
126
Value of property depreciates 10% per year. Present value is 810,000. What was its value 2 years ago?
Answer:
1000000
Let old value be x. x * (0.9)^2 = 810,000. x * 0.81 = 810,000. x = 1,000,000.
127
Value of a car depreciates by 20% every year. If current value is 400,000, what will be its value after 2 years?
Answer:
256000
Value = 400,000 * (1 - 0.20)^2 = 400,000 * (0.8)^2 = 400,000 * 0.64 = 256,000.
128
A town's population is 50,000. It increases by 10% every year. What will be the population after 1 year?
Answer:
55000
Increase = 10% of 50000 = 5000. New population = 50000 + 5000 = 55000.
129
The population of a village is 8000. It decreases by 5% annually. What will it be after 2 years?
Answer:
7220
P = 8000 * (1 - 0.05)^2 = 8000 * 0.95^2 = 8000 * 0.9025 = 7220.
130
The population of a town is 10,000. It increases by 10% in the first year and 20% in the second year. What is the population after 2 years?
Answer:
13200
Population after year 1 = 10000 * 1.10 = 11000. Population after year 2 = 11000 * 1.20 = 13200.