To determine the principal sum, let's analyze the given statements.
Statement II: The sum amounts to Rs 750 in five years at a simple interest rate.
Statement III: The rate of interest is 8% per annum.
Using Statements II and III, we can find the principal sum by using the formula for simple interest: \(A = P(1 + \frac{rt}{100})\), where \(A\) is the amount, \(P\) is the principal, \(r\) is the rate of interest, and \(t\) is the time in years.
Here, \(A = 750\), \(r = 8\%\), and \(t = 5\) years.
Substitute these values into the formula:
\(750 = P(1 + \frac{8 \times 5}{100})\)
\(750 = P(1 + \frac{40}{100})\)
\(750 = P(1.4)\)
Solving for \(P\):
\(P = \frac{750}{1.4}\)
\(P = 535.71\)
Therefore, the principal sum is Rs 535.71.
Hence, using Statements II and III only, the principal sum can be determined.