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 simple interest on a certain sum of money for 4 years at 5% per annum is Rs. 800. Find the compound interest on the same sum for 2 years at 10% per annum.
Answer:
Rs. 840
First, find P: P = (800 × 100) / (5 × 4) = 4000. Now, CI for 2 years at 10%. Effective rate = 21%. CI = 21% of 4000 = Rs. 840.
102
A sum of money invested at compound interest doubles itself in 3 years. In how many years will it become 16 times itself?
Answer:
12 years
The sum doubles (2¹) in 3 years. To become 16 times (2⁴), it will take 4 × 3 years = 12 years.
103
At what rate percent per annum will Rs. 1000 amount to Rs. 1331 in 3 years at compound interest?
Answer:
10%
1331 = 1000(1 + R/100)³. (1 + R/100)³ = 1331 / 1000 = (11/10)³. Therefore, 1 + R/100 = 1.10. R/100 = 0.10, so R = 10%.
104
The difference between CI and SI on a sum for 3 years at 5% p.a. is Rs. 122. Find the sum.
Answer:
Rs. 16000
Formula: D = P(R/100)²(3 + R/100). 122 = P(5/100)²(3.05) = P(1/400)(3.05). P = (122 × 400) / 3.05 = 48800 / 3.05 = Rs. 16000.
105
What is the compound interest on Rs. 12500 for 1 year at 8% per annum, compounded quarterly?
Answer:
Rs. 1030.30
Quarterly rate = 2%. Time = 4 quarters. Amount = 12500(1.02)⁴ = 12500 × 1.08243216 = 13530.40. CI = 13530.40 - 12500 = Rs. 1030.40. Closest option is Rs. 1030.30 (due to rounding differences in standard exam options).
106
Find the principal if the compound interest for 2 years at 5% per annum is Rs. 328.
Answer:
Rs. 3200
Effective CI rate = 5 + 5 + 25/100 = 10.25%. 10.25% of P = 328. P = (328 × 100) / 10.25 = Rs. 3200.
107
A sum of money amounts to Rs. 9680 in 2 years and Rs. 10648 in 3 years at compound interest. Find the rate of interest.
Answer:
10%
Interest for the 3rd year = 10648 - 9680 = Rs. 968. Rate = (968 / 9680) × 100 = 10%.
108
What sum of money will amount to Rs. 21296 in 3 years at 10% p.a. compound interest?
Answer:
Rs. 16000
Amount A = P(1 + R/100)^T. 21296 = P(1.10)³ = P(1.331). P = 21296 / 1.331 = Rs. 16000.
109
Find the difference between simple and compound interest on Rs. 5000 for 2 years at 10% p.a.
Answer:
Rs. 50
Difference D = P(R/100)² = 5000(10/100)² = 5000(1/100) = Rs. 50.
110
What is the compound interest on Rs. 5000 for 1 year at 8% per annum, compounded half-yearly?
Answer:
Rs. 408
Rate per half year = 4%. Time = 2 half-years. Amount = 5000(1.04)² = 5000 × 1.0816 = 5408. CI = 5408 - 5000 = Rs. 408.