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
191
A sum of money amounts to Rs. 5200 in 5 years and to Rs. 5680 in 7 years at simple interest. The rate of interest per annum is:
Answer:
6%
SI for 2 years (7-5) = 5680 - 5200 = Rs. 480. SI for 1 year = 240. SI for 5 years = 240 × 5 = 1200. Principal = 5200 - 1200 = 4000. Rate = (240 × 100) / (4000 × 1) = 6%.
192
If the simple interest on a sum of money is 1/9 of the principal, and the number of years is equal to the rate percent per annum, find the rate percent.
Answer:
3.33%
SI = (1/9)P. T = R = x. (1/9)P = (P × x × x)/100 => x² = 100/9 => x = 10/3 = 3.33%. So the rate is 3.33%.
193
What will be the ratio of simple interest earned by a certain amount at the same rate of interest for 3 years and that for 8 years?
Answer:
3:8
Since SI = (P × R × T)/100, for constant P and R, SI is directly proportional to T. Hence, the ratio of SI for 3 years to 8 years is exactly the ratio of the times: 3:8.
194
A man took a loan from a bank at the rate of 12% p.a. simple interest. After 3 years he had to pay Rs. 5400 interest only for the period. The principal amount borrowed by him was:
Answer:
Rs. 15000
P = (SI × 100) / (R × T) = (5400 × 100) / (12 × 3) = 540000 / 36 = Rs. 15000.
195
Reena took a loan of Rs. 1200 with simple interest for as many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, what was the rate of interest?
Answer:
6
Let Rate = Time = x. SI = (P × R × T) / 100 => 432 = (1200 × x × x) / 100. This gives 12x² = 432, so x² = 36. Therefore, x = 6. The rate of interest was 6%.
196
A sum of Rs. 1600 gives a simple interest of Rs. 252 in 2 years and 3 months. The rate of interest per annum is:
Answer:
7%
Time T = 2 years 3 months = 2 + 3/12 = 2.25 years = 9/4 years. R = (SI × 100) / (P × T) = (252 × 100) / (1600 × 9/4) = 25200 / 3600 = 7%.
197
An automobile financier claims to be lending money at simple interest, but he includes the interest every six months for calculating the principal. If he is charging an interest of 10%, the effective rate of interest becomes:
Answer:
10.25%
Since interest is added to the principal every six months, it acts like compound interest compounded half-yearly. Rate = 10% p.a. = 5% per half year. Effective annual rate = 5 + 5 + (5×5)/100 = 10.25%.
198
A sum of money amounts to Rs. 850 in 3 years and to Rs. 925 in 4 years at some rate of simple interest. The sum is:
Answer:
Rs. 625
SI for 1 year = 925 - 850 = Rs. 75. SI for 3 years = 75 × 3 = Rs. 225. Principal = Amount for 3 years - SI for 3 years = 850 - 225 = Rs. 625.
199
What is the simple interest on Rs. 2500 at 6% p.a. from 4th March to 16th May in the same year?
Answer:
Rs. 30
Calculate the number of days: March (31-4) = 27 days, April = 30 days, May = 16 days. Total = 73 days. Time T = 73/365 = 1/5 years. SI = (2500 × 6 × 1/5) / 100 = (500 × 6) / 100 = Rs. 30.
200
Rs. 12000 is deposited at compound interest. If it doubles in 5 years, what will it be after 20 years?
Answer:
Rs. 192000
In CI, the sum grows by a constant multiple over equal time intervals. It doubles (x2) every 5 years. Over 20 years, there are 4 such intervals. So it will multiply by 2⁴ = 16. Total amount = 12000 × 16 = Rs. 192000.