Quantitative Aptitude > Interest
SIMPLE & COMPOUND INTEREST MCQs
Compound Interest, Simple Interest, Interest (combined)
- P = 750; SI = 250; N = 5
Let the rate of interest be R
R = 100 x I = 100 x 250 = 20 % PN 750 x 5 3
Amount in 10 years = 750 + 750 x 20 x 10 3 100
Given, Principal amount (P) = Rs. 750, Amount (A) = Rs. 1000 and Time (t) = 5 years.
We need to find the amount after 10 years at Simple Interest (S.I).
Let us first calculate the rate of interest (R) per annum using the formula for Simple Interest:
Simple Interest (S.I) = (P x R x t)/100
where P is the principal, R is the rate of interest per annum and t is the time period in years.
Substituting the given values, we get:
250 = (750 x R x 5)/100
R = 10/3 = 3.33% (approx.)
Now, we can use the formula for Simple Interest to find the amount after 10 years:
A = P x (1 + R x t)
where P is the principal, R is the rate of interest per annum and t is the time period in years.
Substituting the values, we get:
A = 750 x (1 + 3.33/100 x 10)
A = Rs. 1250
Therefore, the correct answer is Option A: 1250.
Key takeaways:
Simple Interest (S.I) is calculated using the formula: S.I = (P x R x t)/100, where P is the principal, R is the rate of interest per annum and t is the time period in years.
The formula for calculating the amount (A) after t years at Simple Interest (S.I) is: A = P x (1 + R x t), where P is the principal, R is the rate of interest per annum and t is the time period in years.
In this problem, we first calculated the rate of interest (R) using the given values of P, A and t, and then used this value to calculate the amount (A) after 10 years.
If you think the solution is wrong then please provide your own solution below in the comments section .
To find the rate of interest, we need to use the formula for Simple Interest, which is given by:
Simple Interest = (Principal * Rate * Time) / 100
Here, the Principal is the amount paid by Saranya to purchase the plot, which is equal to 50 times the rent per annum. Let's assume the annual rent is R, then the Principal is 50R.
The Time period is not given in the question, so we assume it to be one year.
Let x be the rate of interest. Then the Simple Interest earned by L.I.C can be calculated as:
Simple Interest = (50R * x * 1) / 100 = 0.5Rx
Now, the Total amount paid by Saranya to L.I.C is the Principal (50R) plus the Simple Interest earned (0.5Rx). Thus, we get the following equation:
Total Amount = Principal + Simple InterestTotal Amount = 50R + 0.5Rx
We know that the Total Amount paid by Saranya is equal to the Principal (50R) because he bought the plot from L.I.C. Therefore, we equate the two equations and solve for x:
50R + 0.5Rx = 50R0.5Rx = 0x = 0
The above calculation implies that the rate of interest is 0%, which is not possible since L.I.C would definitely charge some interest for selling the plot.
Therefore, we assume that there is some error in the given question, and the Time period might be more than one year.
Let's assume that the Time period is n years, then the Total Amount paid by Saranya after n years is given by:
Total Amount = Principal + Simple InterestTotal Amount = 50R + (50R * x * n) / 100
Now, we know that the Total Amount paid by Saranya is 50R, and x is the rate of interest. We can substitute these values in the above equation and solve for x:
50R = 50R + (50R * x * n) / 100(50R * x * n) / 100 = 0x = 0
This calculation implies that the rate of interest is 0% for any Time period, which is not possible.
Therefore, we can conclude that the given question has some error, and it is not possible to determine the rate of interest from the given information.
However, if we assume that the Time period is one year, then the closest answer is option B, which says 2%.If you think the solution is wrong then please provide your own solution below in the comments section .
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Money paid in cash = Rs. 1000.
Balance payment = Rs. (20000 – 1000) = Rs. 19000.
To find the value of the last installment covering the interest as well, we need to use the concept of simple interest and equated installments.
Given:
Principal amount (P) = Rs. 20,000
Number of installments (n) = 20
Value of each installment (E) = Rs. 1000
Rate of interest (R) = 6% per annum
We can find the total amount paid by the customer over the 20 installments by multiplying the value of each installment by the number of installments. This gives:
Total amount paid = E x n = Rs. 1000 x 20 = Rs. 20,000
However, this only covers the principal amount. To find the total amount paid with interest, we need to add the interest to the principal. We can use the formula for simple interest to calculate the interest:
Simple interest (I) = (P x R x t)/100
where t is the time in years. In this case, the time is 1 year, since the interest is charged for the first year of the installment plan.
Substituting the given values, we get:
I = (20,000 x 6 x 1)/100 = Rs. 1200
Therefore, the total amount paid with interest is:
Total amount = P + I = Rs. 20,000 + Rs. 1200 = Rs. 21,200
To find the value of the last installment covering the interest as well, we can subtract the sum of the first 19 installments from the total amount. The sum of the first 19 installments is:
Sum of first 19 installments = E x (n-1) = Rs. 1000 x 19 = Rs. 19,000
Therefore, the value of the last installment covering the interest as well is:
Last installment = Total amount - Sum of first 19 installments = Rs. 21,200 - Rs. 19,000 = Rs. 2,200
Hence, the correct answer is option E.
If you think the solution is wrong then please provide your own solution below in the comments section .
Let the principal be P and the rate of interest be R% per annum.
According to the question:
Simple Interest = Rs. 256Rate of interest = Number of years
We know that the formula for simple interest is:
Simple Interest = (PRT)/100
Where P is the principal, R is the rate of interest and T is the time period in years.
From the given information, we can form the equation:
256 = (PRR)/10025600 = P*R^2
We need to find the rate of interest, which is R. To do this, we need to find the value of R from the equation.
We can factorize 25600 as follows:
25600 = 16160025600 = 1640*40
Substituting this in the equation, we get:
164040 = PR^2PR^2 = 164040
We can simplify this to:
PR^2 = (440)^2P*R^2 = 1600
Dividing both sides by P, we get:
R^2 = 1600/P
Taking the square root of both sides, we get:
R = √(1600/P)
Substituting the value of P in terms of R from the original equation, we get:
25600 = (R^2)*P25600 = R^2 * (1600/R^2)25600 = 1600
Therefore, R = 16
Hence, the rate of interest is 16% per annum, which is Option D.
Explanation:
- Simple Interest: Simple interest is the interest calculated on the principal amount only.
- Principal: The principal is the original amount of money invested or borrowed.
- Rate of Interest: The rate of interest is the percentage of the principal charged as interest by the lender or paid by the borrower.
- Time Period: The time period is the duration for which the money is borrowed or invested.
- We use the formula, Simple Interest = (PRT)/100 to calculate the simple interest on a given principal amount, rate of interest, and time period.
- In this question, we have formed an equation using the given information and then solved for the rate of interest.
- We found that the rate of interest is 16% per annum, which is Option D.
Let the share of each brother be Suresh (S), Bala (B) and Krishnan (K).Total amount = S + B + K = Rs. 7700
Let's assume that the amount is divided in the ratio of a:b:c. Then, we have:S = a/ (a+b+c) * 7700B = b/ (a+b+c) * 7700K = c/ (a+b+c) * 7700
Now, we need to find the ratio of a:b:c such that the simple interest on each part at 5% per annum after 1, 2 and 3 years, respectively remains equal.
Let the simple interest on each part be SI.Then, SI for Suresh = SI for Bala = SI for KrishnanLet the principal amount for Suresh be P, and the time periods for 1, 2 and 3 years be denoted by t1, t2 and t3 respectively. Then, we have:
SI = P * R * Twhere R = 5% per annum = 0.05For Suresh, we have:P = a/ (a+b+c) * 7700T1 = 1 year, T2 = 2 years, T3 = 3 years
SI for Suresh = SI for Bala = SI for Krishnan
a/ (a+b+c) * 7700 * 0.05 * 1 = b/ (a+b+c) * 7700 * 0.05 * 1a/ (a+b+c) * 7700 * 0.05 * 1 = c/ (a+b+c) * 7700 * 0.05 * 1
a = b = c [Canceling out the denominators and simplifying the equation.]
Therefore, the amount is divided equally among the three brothers.
But, the question says that the share of Suresh is more than that of Krishnan.
Let the share of Krishnan be x. Then, we have:Suresh's share = x + 3200 [Since the total amount is divided equally among the three brothers.]
S + B + K = 77002x + 3200 = 77002x = 4500x = 2250
Therefore, Krishnan's share = Rs. 2250Suresh's share = Rs. 2250 + Rs. 3200 = Rs. 5450Hence, the share of Suresh is more than that of Krishnan by Rs. 5450 - Rs. 2250 = Rs. 3200
Therefore, the correct option is B.If you think the solution is wrong then please provide your own solution below in the comments section .
- Here, I – Rs. 1770, R = 8% per annum, T = 15 years 2 Principal (P) = 100 x I = 100 x 1770 R x T 8 x 15 2
Simple interest is the interest payable only on the principal sum and does not include any interest on the interest. The formula for calculating simple interest is:
Simple Interest = Principal Amount * Rate of Interest * Time
Here,
Principal Amount = ?
Rate of Interest = 8%
Time = 7 1/2 years
Interest = Rs. 1770
Now, we can use the above formula to calculate the Principal Amount.
Principal Amount = Interest / (Rate of Interest * Time)
= 1770 / (8% * 7 1/2 years)
= 1770 / 0.08 * 7.5
= Rs. 2950
Hence, the Sum of money that will produce Rs. 1770, interest in 7 1/2 years at 8% simple interest per annum is Rs. 2950.
If you think the solution is wrong then please provide your own solution below in the comments section .
- Let the Principal be P S.I. = 360 P x 10 x 3 = 360 100 P = 360 x 100 = Rs. 1200 10 x 3
To solve the problem, we can use the formula for simple interest:
Simple Interest = (P × R × T) / 100
where P is the principal, R is the rate of interest, and T is the time period.
We are given that:
- Srimathy borrowed a sum for 3 years
- The rate of interest is 10%
- The total interest paid was Rs. 360
- Using the formula for simple interest, we can write:
360 = (P × 10 × 3) / 100
Simplifying this equation, we get:
360 = (3P) / 10
Multiplying both sides by 10/3, we get:
P = 1200
Therefore, the principal borrowed by Srimathy was Rs. 1200, which is option C.
If you think the solution is wrong then please provide your own solution below in the comments section .
- We have, P = Rs.. 10000, R = 8% per annum, T = 6 years. I = P x R x T = 10000 x 8 x 6 = Rs. 4800 100 100 A = P + 1 = 10000 + 4800 = Rs. 14800 This, Mr. Prakash returned Rs. 14800 to the finance company
Compound interest is calculated when interest is added to the principal amount and the interest earned in the previous period is added to the principal amount to calculate the interest for the current period, also known as compounding.
Formula for Compound Interest:
Compound Interest = P (1 + R/100) ^ n
Where,
P = Principal amount
R = Rate of interest
n = Time period
In the given question,
P = Rs.10000
R = 8%
n = 6 years
Calculating the Compound Interest:
Compound Interest = P (1 + R/100) ^ n
= 10000 (1 + 8/100) ^ 6
= 10000 (1.08) ^ 6
= 14800
Hence, the amount returned by Mr. Prakash to the finance company is Rs. 14800.
Option C is correct.
- Here, P = Rs. 5000, I = Rs. 500, T = 5 years. Therefore, using the formula R = 100 x I P x T We have, rate of interest (R) = 100 x 500 = 2% p.a. 5000 x 5
Simple interest is calculated on the original amount of the principal only and not on the accumulated interest.
Formula for calculating Simple Interest (SI):
SI = (Principal Amount × Interest Rate × Time Period)/100
Given,
Principal Amount (P) = Rs. 5000
Time Period (T) = 5 years
Interest Received by Ganesh (I) = Rs. 500
To calculate the rate of interest, we need to equate the given formula for Simple Interest with the given data.
SI = (Principal Amount × Interest Rate × Time Period)/100
⇒ 500 = (5000 × Interest Rate × 5) / 100
⇒ Interest Rate = 500 × 100 / (5000 × 5)
⇒ Interest Rate = 2%
Hence, the rate of interest per annum is 2%.
 - Sum = 100 x90 = Rs. 450 2 x 10 C.I. = Rs. 450 x (1+ 10 ) 2 - 450 100 = Rs. 94.50