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The compound interest on a certain sum for 2 years at 10% per annum is Rs 525. The simple interest on the same sum for double the time at half the rate percent per annum is:
  • a)
    Rs 400
  • b)
    Rs 500
  • c)
    Rs 600
  • d)
    Rs 800
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
The compound interest on a certain sum for 2 years at 10% per annum is...
Let the sum be Rs P.
Then, [P (1 + 10/100)2 – P] = 525
P = (11/10)2 – 1 = 525
P = (525 × 100)/21 = 2500
Therefore, sum = Rs 2500
S.I. = (2500 × 5 × 4)/100 = Rs 500
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Most Upvoted Answer
The compound interest on a certain sum for 2 years at 10% per annum is...
Understanding Compound Interest
To find the principal amount (P) using the compound interest formula, we start with the information given:
- **Compound Interest (CI)** for 2 years = Rs 525
- **Rate of Interest (R)** = 10% per annum
- **Time (T)** = 2 years
The formula for compound interest is:
\[ CI = P \times \left( \left(1 + \frac{R}{100}\right)^T - 1 \right) \]
Substituting the values:
\[ 525 = P \times \left( \left(1 + \frac{10}{100}\right)^2 - 1 \right) \]
Calculating:
\[ \left(1 + 0.1\right)^2 = 1.21 \]
So:
\[ 525 = P \times (1.21 - 1) \]
\[ 525 = P \times 0.21 \]
Now, solving for P:
\[ P = \frac{525}{0.21} = 2500 \]

Calculating Simple Interest
Now that we have the principal amount (P = Rs 2500), we can calculate the simple interest for double the time at half the rate.
- **New Time (T)** = 4 years (double the time)
- **New Rate (R)** = 5% per annum (half of 10%)
The formula for simple interest (SI) is:
\[ SI = \frac{P \times R \times T}{100} \]
Substituting the values:
\[ SI = \frac{2500 \times 5 \times 4}{100} \]
Calculating:
\[ SI = \frac{50000}{100} = 500 \]

Final Answer
The simple interest on the sum for double the time at half the rate per annum is Rs 500. Thus, the correct answer is option 'B'.
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The compound interest on a certain sum for 2 years at 10% per annum is Rs 525. The simple interest on the same sum for double the time at half the rate percent per annum is:a)Rs 400b)Rs 500c)Rs 600d)Rs 800Correct answer is option 'B'. Can you explain this answer?
Question Description
The compound interest on a certain sum for 2 years at 10% per annum is Rs 525. The simple interest on the same sum for double the time at half the rate percent per annum is:a)Rs 400b)Rs 500c)Rs 600d)Rs 800Correct answer is option 'B'. Can you explain this answer? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about The compound interest on a certain sum for 2 years at 10% per annum is Rs 525. The simple interest on the same sum for double the time at half the rate percent per annum is:a)Rs 400b)Rs 500c)Rs 600d)Rs 800Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The compound interest on a certain sum for 2 years at 10% per annum is Rs 525. The simple interest on the same sum for double the time at half the rate percent per annum is:a)Rs 400b)Rs 500c)Rs 600d)Rs 800Correct answer is option 'B'. Can you explain this answer?.
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