# Simple Interest - Aptitude Questions and Answers - RejinpaulPlacement

DATA SUFFICIENCY TYPE QUESTIONS
Directions: (64 to 68)
Each of the questions given below consists of a statement and/or a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statements is/are sufficient to answer the given question. Read both the statements and
Given answer (a) if the data in statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.
Given answer (b) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question
Given answer (c)if the data either in Statement I or in Statement II alone are sufficient to answer the question
Given answer (d) if the data even in both Statement I and II together are not sufficient to answer the questions
Given answer (e) if the data in both Statement I and II together are necessary to answer the question.

64.
What is the rate of simple interest? [Bank P.O. 2003]
I. The total interest earned was Rs. 4000.
II. The sum was invested for 4 years.
Answer: (d) if the data even in both Statement I and II together are not sufficient to answer the questions

Solution:   We know that, R = [(100 * S.I.)/(P * T)]

Now, I gives, S.I. = Rs. 4000.
II gives , T =4 years.

But, P is unknown . So, we cannot find R.
So, given data is insufficient to get R.

65.
The simple interest on a sum of money is Rs. 50. What is the sum? [R.B.I. 2003]
I. The interest rate is 10% p.a.
II. The sum earned simple interest in 10 years.
Answer: e) if the data in both Statement I and II together are necessary to answer the question.

Solution:   Given : S.I. = Rs. 50.

I gives, R = 10% p.a.
II gives, T = 10 years.

Sum = [(100 * S.I.)/(T * R)] = Rs. [(100 * 50)/(10 * 10)] = Rs. 50.
Thus, I and II together gives the answer.

66.
How much money did X invest?
I. An increase in the rate of interest from 4   7/8% to 5   1/8% per annum increases his yearly income by Rs. 25.
II. The sum invested gets doubled, when invested at 8% p.a. for 12   1/2 years.
Answer: a) if the data in statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question.

Solution:   Suppose X invests Rs. x.

I gives : R1 = 39/8 %, R2 = 41/8 %
Increase in S.I. = Rs. 25.

=> [(x * 1 * (41/8))/100] - [(x * 1 * (39/8))/100] = 25.
=> (41x - 39x) = (25 * 800)
=> x = [(25 * 800)/2] = 10000.

Thus, I only gives the answer.

II gives, S.I. = Rs. x, R = 8% and T = 25/2 years.

P = [(100 * S.I)/(R * T)] = [((100 * x)/(8 * 25)) * 2]
Thus, P is not obtained.

I alone is sufficient to get the answer and II in not sufficient to get the answer.

67.
What percentage of simple interest per annum did Anand pay to Deepak? [I.B.P.S. 2002]
I. Anand borrowed Rs. 8000 from Deepak for four years.
II. Anad returned Rs. 8800 to Deepak at teh end of two years and settled the loan.
Answer: e) if the data in both Statement I and II together are necessary to answer the question.

Solution:   Let the rate be R% p.a.

I gives, P = Rs. 8000 and T = 4 years.
II gives, S.I. = Rs. (8800 - 8000) = Rs. 800.

R = [(100 * S.I.)/(P * T)] = [(100 * 800)/(8000 * 4)] % = 2   1/2 % p.a.

Thus, I and II both are needed to get the answer.

68.
What is the sum which earned interest? [NABARD, 2002]
I. The total simple interest was Rs. 7000 after 7 years.
II. The total of sum and simple interest was double of the sum after 5 years.
Answer: e) if the data in both Statement I and II together are necessary to answer the question.

Solution:   Let the sum be Rs. x.

I gives, S.I. = Rs. 7000 and T = 7 years.
II gives, Sum + S.I. for 5 years = 2 * Sum
=> Sum = S.I. for 5 years.

Now, S.I for 7 years = Rs. 7000.
S.I for 1 year = Rs. (7000/7) = Rs. 1000.
S.I. for 5 years = Rs. (1000 * 5) = Rs. 5000.

Thus, I and II both are needed to get the answer.

Directions (Questions 69 to 70) : Each of the questions given below consists of a question followed by three statements. You have to study the question and the statements and decide which of the statement(s) is/are necessary to answer the question.
69.
What is the principal sum?
I. The sum amounts to Rs. 690 in 3 years at S.I.
II. The sum amounts to Rs. 750 in 5 years at S.I.
III. The rate of interest is 5% p.a.
Answer: e) Any two of the three

Solution:   Clearly, any of the three will give us the answer.
70.
In how many years will a sum of money put at simple interest treble itself?
I. The interest earned in 4 years is half the sum.
II. The rate of interest is 12   1/2 %.
III. The sum doubles itself in 8 years at simple interest.
Answer: e) Any one of the three

Solution:   Let sum be Rs. x. Then, S.I. = Rs. (3x - x) = Rs. 2x, T = ?

I gives, When T = 4, then S.I. = Rs. x/2.
R = [(100 * S.I)/(P * T)] = [100 * (x/2) * (1/x) * (1/4)] = 12 1/2 % p.a.

Now, Sum = Rs. x, S.I. = Rs. 2x, R = 25/2 % p.a., T = ?

T = [(100 * S.I)/(P * R)] = [((100 * 2x)/(x * 25)) * 2] = 16 years.
Thus, I only gives the answer.

II gives, R = 25/2 % p.a.
T = [(100 * S.I)/(P * R)]= [((100 * 2x)/(x * 25)) * 2] = 16 years.

Thus, II only also gives the answer.

III gives, R = 5% p.a.
T = [(100 * S.I)/(P * R)] = [(100 * 2x)/(x * 5)] = 40 years.

Thus, III only also gives the answer.