By mistake a clerk calculated the simple interest on principal for 5 m...
Calculation of Original Sum
Given:
- Principal was calculated for 5 months at 6.5% per annum instead of 6 months at 5.5% per annum.
- Error in calculation was 25.40.
To find: Original sum (principal).
Formula Used
The formula for simple interest is:
Simple Interest = (P * R * T) / 100
where,
- P = Principal
- R = Rate of interest
- T = Time in years
Solution
Let the original sum be 'P'.
According to the given data,
- Principal was calculated for 5 months at 6.5% per annum.
- Instead, it should have been calculated for 6 months at 5.5% per annum.
- The error in calculation was 25.40.
Using the formula for simple interest, we can write:
Simple Interest = (P * R * T) / 100
For the incorrect calculation:
- P = Principal calculated for 5 months at 6.5% per annum
- R = 6.5/12 = 0.542% per month (monthly rate)
- T = 5/12 years
- Simple Interest = Error in calculation = 25.40
Substituting these values in the formula, we get:
25.40 = (P * 0.542 * 5/12) / 100
Solving for P, we get:
P = (25.40 * 100) / (0.542 * 5/12) = 9333.33 (approx.)
Therefore, the original sum (principal) is 9333.33 (approx.).
Explanation
The given problem involves finding the original sum (principal) when there is an error in the calculation of simple interest due to incorrect rate and time. To solve the problem, we use the formula for simple interest and substitute the given values to find the unknown value (principal). The solution involves algebraic manipulation and simplification of the formula to obtain the final answer. It is important to understand the formula and the given data to correctly solve the problem.