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
101
The price of an article is cut by 10%. To restore it to its former value, the new price must be increased by?
Answer:
11.11%
Let original price = 100. Cut by 10% = 90. To get back to 100, increase must be 10 on a base of 90. Percentage = (10 / 90) * 100 = 11.11%.
102
40% of the people read newspaper X, 50% read newspaper Y, and 10% read both. What percentage read neither?
Answer:
20%
Read at least one = Read X + Read Y - Read both = 40 + 50 - 10 = 80%. Read neither = 100% - 80% = 20%.
103
In an examination, a student who gets 20% marks fails by 5 marks. Another gets 30% marks and gets 20 marks more than pass marks. Find the pass percentage.
Answer:
22%
Difference in % = 10%. Difference in marks = 20 - (-5) = 25. 10% = 25 -> Total = 250. Pass marks = 20% of 250 + 5 = 50 + 5 = 55. Pass % = (55 / 250) * 100 = 22%.
104
If the price of an item is increased by 30% and then allowed two successive discounts of 10% and 10%. The final price compared to the original is?
Answer:
5.3% increase
Let original be 100. Increased to 130. Successive discounts: 130 * 0.9 = 117. Then 117 * 0.9 = 105.3. Final price is 105.3, which is a 5.3% increase.
105
Out of two numbers, 40% of the greater number is equal to 60% of the smaller. If the sum of the numbers is 150, then the greater number is?
Answer:
90
Let G be greater, S be smaller. 0.4G = 0.6S -> 2G = 3S -> G/S = 3/2. Ratio is 3:2. Sum is 5 parts = 150. 1 part = 30. Greater = 3 parts = 90.
106
If 30% of A = 0.25 of B = 1/5 of C, then A : B : C is?
Answer:
10 : 12 : 15
3/10 A = 1/4 B = 1/5 C = k. A = 10k/3, B = 4k, C = 5k. Multiply by 3: A=10k, B=12k, C=15k. Ratio is 10:12:15.
107
A student multiplied a number by 3/5 instead of 5/3. What is the percentage error in the calculation?
Answer:
64%
Let number be 15. Correct result = 15 * (5/3) = 25. Incorrect = 15 * (3/5) = 9. Error = 25 - 9 = 16. % Error = (16 / 25) * 100 = 64%.
108
In a library, 20% of books are in Hindi, 50% of the remaining in English, and 30% of the remaining in French. The remaining 6300 books are regional. Total books?
Answer:
22500
Let total be x. Remaining = x * 0.8 * 0.5 * 0.7 = 0.28x. 0.28x = 6300. x = 6300 / 0.28 = 22500.
109
A man gave 30% of his money to his wife, 40% of the remainder to his son, and the remaining Rs 4200 to his daughter. Find the total money he had.
Answer:
10000
Let total be x. After wife, 70% left. After son, 60% of 70% left = 42% left. 42% of x = 4200. x = 4200 / 0.42 = 10000.
110
If the numerator of a fraction is increased by 20% and the denominator is decreased by 10%, the fraction becomes 16/21. What was the original fraction?
Answer:
4/7
Let fraction be x/y. (x * 1.2) / (y * 0.9) = 16/21. (x/y) * (12/9) = 16/21. (x/y) * (4/3) = 16/21. x/y = (16/21) * (3/4) = 4/7.