Aptitude - Simple Interest - Discussion
Discussion Forum : Simple Interest - Data Sufficiency 2 (Q.No. 1)
Directions to Solve
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.
1.
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: Option
Explanation:
Clearly, any two of the three will give us the answer.
Correct answer is (E).
Discussion:
31 comments Page 4 of 4.
HRK said:
4 years ago
Using I and III;
Let S.I be 'x'.
Hence, P = 690 - x.
x = [(690- x) *5*3] / 100.
Solve for 'x' and find P.
Similarly, it works using II and III
Now, using I and II.
Let x be the interest rate.
Hence, P + 3Px = 690, simplify to P(1+3x) =690 -----> (a)
P + 5Px = 750, simplify to P(1+5x)=750 -----> (b).
Now dividing a by b, P gets canceled and solves for x.
x = 0.05 or 5%.
Now substitute x in the equation a or b to get P.
So we can use any of the three to solve.
Thanks.
Let S.I be 'x'.
Hence, P = 690 - x.
x = [(690- x) *5*3] / 100.
Solve for 'x' and find P.
Similarly, it works using II and III
Now, using I and II.
Let x be the interest rate.
Hence, P + 3Px = 690, simplify to P(1+3x) =690 -----> (a)
P + 5Px = 750, simplify to P(1+5x)=750 -----> (b).
Now dividing a by b, P gets canceled and solves for x.
x = 0.05 or 5%.
Now substitute x in the equation a or b to get P.
So we can use any of the three to solve.
Thanks.
(3)
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