Quantitative Aptitude is the section that decides most competitive exam results, because it is where speed and accuracy matter more than syllabus coverage. These questions run across number system, percentage, profit and loss, ratio and proportion, averages, time and work, time speed and distance, simple and compound interest, mensuration, and data interpretation. Every solution shows the working, including the shortcut where one exists, so you can compare your method against a faster one.
Two articles are sold for ₹960 each. On the first article, there is a profit of 20%, and on the second, there is a loss of 20%. What is the net loss percentage on the entire transaction?
Answer: C
Step 1: For first article with 20% profit: SP = ₹960, so CP₁ = 1960.20 = ₹800.
Step 2: For second article with 20% loss: SP = ₹960, so CP₂ = 0960.80 = ₹1,200.
Step 3: Total CP = 2,000, Total SP = 1,920.
Loss% = (200080) × 100 = 4%.
So option C is correct.
Q.64Easy
A shopkeeper sells pens at ₹12 each, making a profit of 50%. How much does he spend to buy 180 pens?
Answer: A
Step 1: SP = ₹12, Profit = 50%, so CP = 112.50 = ₹8 per pen.
Step 2: Cost for 180 pens = 8 × 180 = ₹1,440.
So option A is correct.
Q.65Easy
At what rate of simple interest per annum will ₹2,400 become ₹2,928 in 2 years?
Answer: B
Step 1: Interest = 2,928 - 2,400 = ₹528.
Step 2: Using SI = (P × R × T) / 100, we get 528 = (2,400 × R × 2) / 100.
Step 3: 528 = 48R, so R = 11% p.a.
Option B is correct.
Q.66Easy
In how many years will ₹3,600 amount to ₹4,392 at 11% simple interest per annum?
Answer: A
Step 1: Interest = 4,392 - 3,600 = ₹792.
Step 2: Using SI = (P × R × T) / 100, we get 792 = (3,600 × 11 × T) / 100.
Step 3: 792 = 396T, so T = 2 years.
Option A is correct.
Q.67Easy
Priya borrowed ₹8,000 from a moneylender at 15% simple interest per annum. If she paid ₹3,600 as interest, for how long did she borrow the money?
Answer: C
Using SI = (P × R × T) / 100, we have 3,600 = (8,000 × 15 × T) / 100.
Step 1: 3,600 = 1,200T.
Step 2: T = 3,1600,200 = 3 years.
Option C is correct.
Q.68Medium
A bank offers 7.5% simple interest per annum on fixed deposits. If Arun deposits ₹12,000, what will be the total amount after 4 years?
Step 2: Amount = Principal + SI = 12,000 + 3,600 = ₹15,600.
Option A is correct.
Q.69Medium
Two equal sums of money are invested at simple interest. The first at 9% p.a. for 5 years and the second at 6% p.a. for 8 years. If the difference in their interests is ₹840, what is the sum invested?
Mohan invested a certain sum at simple interest. If he had invested ₹5,000 more at the same rate, he would have earned ₹1,200 more interest in 4 years. What is the rate of interest per annum?
Answer: B
Step 1: Extra interest earned on ₹5,000 in 4 years = ₹1,200.
Step 2: Using SI = (P × R × T) / 100, we have 1,200 = (5,000 × R × 4) / 100.
Step 3: 1,200 = 200R.
Step 4: R = 1,200200 = 6% p.a.
Option B is correct.
Q.71Easy
Raj invested ₹12,000 at 8% per annum compound interest. What will be the amount after 2 years?
Answer: A
Step 1: Use compound interest formula A = P(1 + r/100)^n.
A sum of money doubles itself at 10% per annum compound interest. In how many years will it double?
Answer: A
Step 1: Use formula 2P = P(1.10)^n where 2P is the doubled amount.
Step 2: Divide by P to get 2 = (1.10)^n.
Step 3: Taking log: n = log(2)/log(1.10) = 0.0301.0414 ≈ 7.2 years.
Q.73Medium
At what rate per annum will ₹25,000 amount to ₹29,160 in 2 years at compound interest?
Answer: A
Step 1: Use formula A = P(1 + r/100)^n.
Step 2: 29160 = 25000(1 + r/100)^2.
Step 3: (1 + r/100)^2 = 2500029160 = 1.1664.
Step 4: 1 + r/100 = √1.1664 = 1.08.
Step 5: r/100 = 0.08, so r = 8% per annum.
Q.74Medium
A company invested ₹40,000 in a scheme offering 10% per annum compound interest. If the interest is compounded quarterly, what will be the maturity amount after 1 year?
Answer: C
Step 1: For quarterly compounding, use A = P(1 + r/400)^(4n).
