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
131
A fraction bears the same ratio to 1/27 as 3/7 does to 5/9. The fraction is:
Answer:
1/35
Let fraction be x. x : 1/27 = 3/7 : 5/9. x / (1/27) = (3/7) / (5/9) => 27x = 27/35. x = 1/35.
132
If a/2 = b/3 = c/5, find (a+b+c)/c.
Answer:
2
Let a/2 = b/3 = c/5 = k. a=2k, b=3k, c=5k. (a+b+c)/c = (2k+3k+5k)/5k = 10k/5k = 2.
133
A bag contains Rs 410 in the form of Rs 5, Rs 2, and Rs 1 coins in the ratio 4:6:9. The number of Rs 2 coins is:
Answer:
60
Coins ratio 4x, 6x, 9x. Value = 5(4x) + 2(6x) + 1(9x) = 20x + 12x + 9x = 41x. 41x = 410 => x = 10. Number of Rs 2 coins = 6x = 60.
134
If 10% of x = 15% of y = 20% of z, find x:y:z.
Answer:
6:4:3
10x = 15y = 20z. Divide by 5: 2x = 3y = 4z = k. x=k/2, y=k/3, z=k/4. Multiply by LCM(2,3,4)=12 to get 6:4:3.
135
Two numbers are in ratio 2:3. If their product is 96, find the sum of the numbers.
Answer:
20
Let numbers be 2x and 3x. Product = 6x^2 = 96 => x^2 = 16 => x = 4. Numbers are 8 and 12. Sum = 8 + 12 = 20.
136
What is the ratio of 40 paise to Rs 2?
Answer:
1:5
Rs 2 = 200 paise. Ratio = 40 : 200. Dividing both by 40 gives 1 : 5.
137
If a, b, c are in continued proportion, then b^2 is equal to:
Answer:
ac
By definition of continued proportion, a/b = b/c. Cross-multiplying gives b^2 = ac.
138
The ratio of two numbers is 3:4 and their sum is 420. The greater of the two numbers is:
Answer:
240
Let numbers be 3x, 4x. Sum = 7x = 420 => x = 60. Greater number = 4x = 4 * 60 = 240.
139
The ratio of the number of men and women in a factory is 3:1. If there are 150 men, the total number of workers is:
Answer:
200
Men = 3x = 150 => x = 50. Total workers = 3x + 1x = 4x = 4 * 50 = 200.
140
What least number must be added to each of the numbers 7, 16, 43, 79 so that they become proportional?
Answer:
5
Let x be added. (7+x)/(16+x) = (43+x)/(79+x). (7+x)(79+x) = (16+x)(43+x) => 553 + 86x + x^2 = 688 + 59x + x^2. 86x - 59x = 688 - 553 => 27x = 135 => x = 5.