Data Sufficiency 2
Practice and master this topic with our carefully crafted questions.
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.
What is the principal sum ?
I. The sum amounts to ₹ 690 in 3 years at S.I.
II. The sum amounts to ₹ 750 in 5 years at S.I.
III. The rate of interest is 5% p.a.
Clearly, any two of the three will give us the answer.
Correct answer is (E).
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
%.
III. The sum doubles itself in 8 years at simple interest.
Let sum be ₹ X. Then,
S.I. = ₹ (3X - X) = ₹ 2X, T = ?
I gives : When T = 4, then S.I. = ₹ X/2.
| Rate = |
 |
100 x S.I. |  % |
|
| P x T |
= (100 x X/2 x 1/X x 1/4)
= 12% p.a.
Now Sum = ₹ X, S.I. = ₹ 2X, R = 25% p.a., T = ?
| Time = |
|
100 x 2X x 2 | years |
= 16 years. |
| X x 25 |
Thus, I only gives the answer.
II gives, R = 25% p.a.
| Time = |
|
100 x 2X x 2 | years |
= 16 years. |
| X x 25 |
Thus, II only also gives the answer.
III gives, R = 5% p.a.
| Time = |
|
100 x 2X | years |
= 40 years. |
| X x 5 |
Thus, III only also gives the answer.
Correct answer is (D)