What sum will yield Rs.540 as Simple Interest at 4% for 7.5 years?

Simple Interest (SI) = Rs. 540

Rate of Interest (R) = 4%

Time (T) = 7.5 years

The formula for Simple Interest is:

​$$SI = \frac{P \times R \times T}{100}$$​​

where:

P is the principal,

R is the rate of interest,

T is the time period.

Substitute the given values into the formula:

​$$P = \frac{540 \times 100}{4 \times 7.5} \\ \ \\P = \frac{540 \times 100}{30} = \frac{54000}{30} = 1800$$​​

Thus, The sum (principal) is Rs. 1800.