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
241
The simple interest on a sum of money for 3 years at 4% per annum is Rs. 240. What would be the compound interest on the same sum at the same rate for 2 years?
Answer:
Rs. 163.20
First, find the principal from the SI details: P = (240 × 100) / (4 × 3) = 24000 / 12 = Rs. 2000. Now, calculate the compound interest for 2 years at 4%. Amount = P(1 + R/100)^T = 2000(1 + 4/100)² = 2000 × 1.04 × 1.04 = 2163.20. CI = Amount - Principal = 2163.20 - 2000 = Rs. 163.20.
242
If the simple interest on a certain sum is 9/16 of the principal and the number of years is equal to the rate percentage per annum, find the rate of interest.
Answer:
7.5%
Let the principal be P. SI = (9/16)P. Given that Time (T) = Rate (R). Using the SI formula: (9/16)P = (P × R × R) / 100. This gives R² = (9 × 100) / 16 = 900 / 16. Taking the square root, R = 30 / 4 = 7.5%.
243
A sum of money triples itself in 20 years at simple interest. Find the rate of interest.
Answer:
10%
Let the principal be P. If it triples, the Amount is 3P, meaning the simple interest earned is 3P - P = 2P. The rate R = (SI × 100) / (P × T) = (2P × 100) / (P × 20) = 200 / 20 = 10%.
244
A sum of money doubles itself in 10 years at simple interest. What is the rate of interest per annum?
Answer:
10%
Let the principal be P. If it doubles, the Amount A = 2P, which means the Simple Interest SI = A - P = 2P - P = P. Using the formula R = (SI × 100) / (P × T), we get R = (P × 100) / (P × 10) = 100 / 10 = 10% per annum.
245
In how many years will Rs. 2500 amount to Rs. 3250 at the rate of 6% per annum simple interest?
Answer:
5 years
First, find the simple interest earned by subtracting the principal from the total amount: SI = 3250 - 2500 = Rs. 750. Then, use the time formula T = (SI × 100) / (P × R). T = (750 × 100) / (2500 × 6) = 75000 / 15000 = 5 years.
246
At what rate percent per annum will a sum of Rs. 6000 yield Rs. 1800 as simple interest in 5 years?
Answer:
6%
To find the rate of interest, we use the formula R = (SI × 100) / (P × T). Given SI = Rs. 1800, P = Rs. 6000, and T = 5 years. Therefore, R = (1800 × 100) / (6000 × 5) = 180000 / 30000 = 6%.
247
If the simple interest on a certain sum of money for 4 years at 5% per annum is Rs. 800, what is the principal amount?
Answer:
Rs. 4000
Using the simple interest formula SI = (P × R × T) / 100, we can rearrange it to find the Principal (P). P = (SI × 100) / (R × T). Substituting the given values: P = (800 × 100) / (5 × 4) = 80000 / 20 = Rs. 4000.
248
What is the simple interest on Rs. 5000 at the rate of 8% per annum for 3 years?
Answer:
Rs. 1200
The formula for simple interest is SI = (P × R × T) / 100. Here, Principal (P) is Rs. 5000, Rate (R) is 8%, and Time (T) is 3 years. Plugging the values into the formula gives SI = (5000 × 8 × 3) / 100 = 120000 / 100 = Rs. 1200.