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 2 of 4.
Effoti said:
7 years ago
By using I and II;
S.I for 2 years = 750-690 = 60 as S.I is divided uniformly for each year, For 1 year = Rs. 30 and For 3 year = 90,
Principal = 690-90 = 600.
By using II and III
As Total Sum = Principal + Interest i.e 750 = P + I (after 5 years) ------> (1)
P = I *100 / R * T = I *100 / 5*5 = 4I,
Put value of P in eq. 1, 750 = 5I , I = 150 and P = 750 -150 = Rs. 600,
Similarly By using I and III.
P = I *100 / R*T = I*100/5*3 = 20/3(I),
690 = 20/3(I) + I , By solving this we get I = Rs.90 and P = 690 - 90 = Rs. 600.
Hence answer is E Any two of the three.
S.I for 2 years = 750-690 = 60 as S.I is divided uniformly for each year, For 1 year = Rs. 30 and For 3 year = 90,
Principal = 690-90 = 600.
By using II and III
As Total Sum = Principal + Interest i.e 750 = P + I (after 5 years) ------> (1)
P = I *100 / R * T = I *100 / 5*5 = 4I,
Put value of P in eq. 1, 750 = 5I , I = 150 and P = 750 -150 = Rs. 600,
Similarly By using I and III.
P = I *100 / R*T = I*100/5*3 = 20/3(I),
690 = 20/3(I) + I , By solving this we get I = Rs.90 and P = 690 - 90 = Rs. 600.
Hence answer is E Any two of the three.
Mansi Arora said:
8 years ago
Hi @Aryan,
We are using here all the three given statements to get the value of P which is not given in the options.
We are using here all the three given statements to get the value of P which is not given in the options.
Vickma said:
9 years ago
AMOUNT = S. I + P.
690 - P = 3PR -> (1).
750 - P = 5PR -> (2).
Divide Eqn 2 by 1;
P = 600.
Use P = 600 in section I & III.
So, the correct option is 'E'.
690 - P = 3PR -> (1).
750 - P = 5PR -> (2).
Divide Eqn 2 by 1;
P = 600.
Use P = 600 in section I & III.
So, the correct option is 'E'.
Kishor said:
9 years ago
Please explain that how to get the answer from eq 1 & 2 only.
Aryan said:
9 years ago
I. Amount after 3 years = 690.
II. Amount after 5 years = 750.
Difference = SI for 2 years = 60.
SI for 1 year = 30,
SI for 3 years = 90,
SI for 5 years = 150,
Thus, Principal = 600.
II. Amount after 5 years = 750.
Difference = SI for 2 years = 60.
SI for 1 year = 30,
SI for 3 years = 90,
SI for 5 years = 150,
Thus, Principal = 600.
Aman kumar shaw said:
9 years ago
How can we get the answer by using I and II. Please tell?
Scientist said:
10 years ago
We can find answer using I and II as follows:.
5PR% = 750 - P.
3PR% = 690 - P --- Dividing them.
---------------.
5 750-P.
= 3 690-P.
3450 - 5P = 2250 - 3P.
1200 = 2P.
P = 600.
Using I and III.
I = PNR%.
5PR% = 750 - P.
3PR% = 690 - P --- Dividing them.
---------------.
5 750-P.
= 3 690-P.
3450 - 5P = 2250 - 3P.
1200 = 2P.
P = 600.
Using I and III.
I = PNR%.
Moncy Kurien said:
1 decade ago
We can find the principal amount by using the options I and II. But how can we find the principal amount using either I and III or II and III? Please explain.
Ashish said:
1 decade ago
For those who need help regarding how to divide equation I and II (as suggested by abcd).
750 = P+(P*R*5)/100 => 75000 = 100P + 5PR. (i).
690 = P+(P*R*3)/100 => 69000 = 100P + 3PR. (ii).
Subtracting (i) & (ii) , we get.
R = 3000/P.
Now substitute it in any one either (i) or (ii) , we get.
P = 600.
Thanks.
750 = P+(P*R*5)/100 => 75000 = 100P + 5PR. (i).
690 = P+(P*R*3)/100 => 69000 = 100P + 3PR. (ii).
Subtracting (i) & (ii) , we get.
R = 3000/P.
Now substitute it in any one either (i) or (ii) , we get.
P = 600.
Thanks.
Ashis said:
1 decade ago
In very simple level I explain to 9 how to get answer using ll & similarly only from (ll) we get P+S.I = 750 & T = 5.
And from (lll) we get R = 5.
Now P+(P*5*5)\100 = 750.
100P+25P = 750*100.
125P = 75000.
P = 600.
And from (lll) we get R = 5.
Now P+(P*5*5)\100 = 750.
100P+25P = 750*100.
125P = 75000.
P = 600.
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