Quantitative Aptitude - MCQ Practice Questions

Step 1: Use SI formula: SI = (P × R × T) / 100.

Step 2: SI = (5000 × 8 × 3) / 100 = $\frac{120000}{100}$ = ₹1,200.

Step 3: Total Amount = Principal + SI = 5000 + 1200 = ₹6,200.

So option A is correct.

Step 1: Find SI = Amount - Principal = 9600 - 8000 = ₹1,600.

Step 2: Use SI = (P × R × T) / 100, so 1600 = (8000 × R × 2) / 100.

Step 3: 1600 = 160R, therefore R = 10%.

So option B is correct.

Step 1: Find SI = 15600 - 12000 = ₹3,600.

Step 2: Use SI = (P × R × T) / 100, so 3600 = (12000 × 6 × T) / 100.

Step 3: 3600 = 720T, therefore T = 5 years.

So option B is correct.

Step 1: Use SI formula: SI = (P × R × T) / 100.

Step 2: SI = (10000 × 5 × 2.5) / 100 = $\frac{125000}{100}$ = ₹1,250.

Step 3: The interest earned is ₹1,250.

So option B is correct.

In simple interest problems, the difference in amounts over different time periods reveals the interest earned, which we can use to find the principal and rate.

Step 1: Find the interest earned between the two periods

The amount after 2 years is ₹7,200 and after 3.5 years is ₹8,400.

Step 2: Calculate the annual simple interest rate

Since ₹1,200 is earned in 1.5 years, the annual interest is:

Step 3: Find the principal using the first condition

Using the simple interest formula: $A=P+I$, where $A$ is the amount, $P$ is the principal, and $I$ is total interest.

After 2 years:

Step 4: Verify with the second condition

After 3.5 years, total interest = $800\times 3.5=₹2,800$

Amount = $5,600+2,800=₹8,400$ ✓

Answer: The principal amount is ₹5,600 (Option D)

To find out who earned more interest, we calculate the simple interest for both Suresh and Amit using the formula:

1. Calculate Suresh's Interest:Principal ($P$) = ₹15,000Rate ($R$) = $7\%$Time ($T$) = $1.5$ years

2. Calculate Amit's Interest:Principal ($P$) = ₹12,000Rate ($R$) = $9\%$Time ($T$) = $2$ years

3. Comparison:Amit's interest: ₹2160Suresh's interest: ₹1575Since $₹2160>₹1575$, Amit earned more interest.

Amit earned more interest, by ₹585.

Simple interest is calculated as a percentage of the principal amount and remains constant each year, making it easier to compare different investment schemes.

Step 1: Calculate Maturity Amount for Scheme A

For Scheme A, we apply the simple interest formula where Principal = ₹20,000, Rate = 6% per annum, and Time = 4 years.

Step 2: Calculate Maturity Amount for Scheme B

For Scheme B, we apply the simple interest formula where Principal = ₹20,000, Rate = 5.5% per annum, and Time = 5 years.

Step 3: Compare the Maturity Amounts

To find which scheme is better and by how much, we subtract the smaller amount from the larger amount.

Since ₹25,500 > ₹24,800, Scheme B gives ₹700 more than Scheme A.

The answer is (C) Scheme B gives ₹700 more than Scheme A.

We use the simple interest formula $SI=\frac{P\times R\times T}{100}$ with amounts in a given ratio to find total principal.

Step 1: Express principals in terms of a variable

Let the three amounts be $2x$, $3x$, and $5x$ (in the ratio 2:3:5).

The total principal is:

Step 2: Calculate interest for each investment

Using $SI=\frac{P\times R\times T}{100}$ with $T=2$ years:

Step 3: Find total interest

Step 4: Solve for x using given total interest

Given that total interest = ₹1,480:

Step 5: Calculate total principal

Answer: The total principal amount invested is ₹13,962.26 (approximately) (Option C)

Step 1: SI for (3.5 - 2) = 1.5 years is (5400 - 4800) = ₹600.

Step 2: SI for 1 year = $\frac{600}{1}$.5 = ₹400.

Step 3: SI for 2 years = 400 × 2 = ₹800.

Principal = 4800 - 800 = ₹4,000.

Rate = ($\frac{400}{4000}$) × 100 = 10% per annum.

Step 4: For amount ₹6,000: SI needed = 6000 - 4000 = ₹2,000.

Time = (2000 × 100) / (4000 × 10) = 5 years.

So option B is correct.

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.

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.

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,$\frac{600}{1}$,200 = 3 years.

Option C is correct.

Step 1: Calculate SI = (P × R × T) / 100 = (12,000 × 7.5 × 4) / 100 = 360,$\frac{000}{100}$ = ₹3,600.

Step 2: Amount = Principal + SI = 12,000 + 3,600 = ₹15,600.

Option A is correct.

Let sum = P.

Step 1: SI₁ = (P × 9 × 5) / 100 = 45P/100.

Step 2: SI₂ = (P × 6 × 8) / 100 = 48P/100.

Step 3: Difference = 48P/100 - 45P/100 = 3P/100 = 840.

Step 4: P = 84,$\frac{000}{3}$ = ₹2,000.

Option A is correct.

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,$\frac{200}{200}$ = 6% p.a.

Option B is correct.

Step 1: Use SI formula = (P × R × T) / 100.

Step 2: SI = (8000 × 6 × 3) / 100 = $\frac{144000}{100}$ = ₹1440.

Step 3: Total Amount = Principal + SI = 8000 + 1440 = ₹9440.

Step 1: SI = Amount - Principal = 6500 - 5000 = ₹1500.

Step 2: Use SI = (P × R × T) / 100, so 1500 = (5000 × R × 5) / 100.

Step 3: 1500 = 250R, therefore R = $\frac{1500}{250}$ = 6% per annum.

In simple interest, the amount grows linearly with time. The key is to find how much interest accrues per year, then work backward to find the principal.

Step 1: Find the interest earned between year 2 and year 4

The amount after 2 years is ₹4200, and after 4 years is ₹4800.

In 2 years (from year 2 to year 4), the interest earned is:

Step 2: Calculate annual simple interest

Since simple interest is constant each year:

Step 3: Find total interest in first 2 years

If the annual interest is ₹300, then in 2 years:

Step 4: Calculate the principal

Using the formula: $\text{Amount}=\text{Principal}+\text{Simple Interest}$

Verification: Principal ₹3600 at SI of ₹300/year gives ₹4200 in 2 years ✓ and ₹4800 in 4 years ✓

Answer: The principal is ₹3600 (Option B)

Step 1: We need SI = P, so SI = ₹12000.

Step 2: Using SI = (P × R × T) / 100, we get 12000 = (12000 × 8 × T) / 100.

Step 3: 12000 = 960T, therefore T = $\frac{12000}{960}$ = 12.5 years.

Step 1: SI for first 2 years = (15000 × 10 × 2) / 100 = ₹3000.

Step 2: After 2 years, remaining principal = 15000 - 3000 = ₹12000.

Step 3: SI on ₹12000 for 1 year = (12000 × 10 × 1) / 100 = ₹1200.

Step 4: Total SI = 3000 + 1200 + ₹1500 (interest on ₹3000 for 1 year) = ₹5700.