What is the rate of interest percent per annum?
I. An amount doubles itself in 5 yr on imple interest,
II. Difference between the compound interest and the simple interest earned on a certain in two years is Rs.400.
III. Simple interest earned per annum is Rs. 400.

Options

A. Only I
B. II and III
C. Any two of three
D. Only I or II and III

Explanation

To determine the rate of interest percent per annum based on the given statements, we will analyze each statement step by step.

### Step 1: Analyze Statement I
**Statement I:** An amount doubles itself in 5 years on simple interest.

Let the principal amount be \( P \). According to the statement, after 5 years, the amount becomes \( 2P \).

Using the formula for simple interest:
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