Aptitude - Simple Interest - Discussion

Discussion Forum : Simple Interest - General Questions (Q.No. 1)
1.
A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:
Rs. 650
Rs. 690
Rs. 698
Rs. 700
Answer: Option
Explanation:

S.I. for 1 year = Rs. (854 - 815) = Rs. 39.

S.I. for 3 years = Rs.(39 x 3) = Rs. 117.

Principal = Rs. (815 - 117) = Rs. 698.

Discussion:
174 comments Page 10 of 18.

Md sahil said:   1 decade ago
Sum amounts to 815 in 3 years.

Sum amounts to 854 in 4 years.

Find sum?

Let the sum be Rs. x.

x = principal amounts in 3 years = Rs. 815.

x = principal amounts in 4 years = Rs. 854.

Principal amount in 1 year = 39 I.

Interest of 1 year = Rs. 39.

Interest of 3 year = 3x39= Rs. 117.

Principal = x.
Rate = ?
Time = 3 years.
For 3 years.

Interest = Rs. 117.
Amount = Rs. 815.
Time = 3 years.

Let rate = R%.
A = p+I.
P = A-I.

= R(815-117).

Rate 698 answer.

Naren said:   10 years ago
815-p = 3*x.1 -----> equation 1.

854-p = 4*x.2 -----> equation 2.

Divide equation 1 with equation 2.

Sumair mudliar said:   10 years ago
@Md Sahil.

Thank you for explaining the solution.

Imran syed said:   10 years ago
For simple interest, this formula is very helpful.

That is I = Prt.

Salomi said:   10 years ago
@Gayathri.

Thank you for explaining the solution clearly.

Kabali said:   10 years ago
@Gayathri nice explanation.

Mick sudama said:   10 years ago
Here you can do it by another S. I 1 yr = 39, in 4 years =156, & principle=854 - 156 = 698.

Aparna said:   9 years ago
Crystal clear explanation, Thanks @Gayathri.

Kitty said:   9 years ago
@Appu.

Your explanation is good, Thank you.

Sachin said:   9 years ago
Thanks @Vikram and @Gayatri.


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