We can use the following formula to calculate the simple interest: Simple Interest = (Principal * Rate * Time) / 100 Where: Principal is the amount of money borrowed. Rate is the interest rate per year. Time is the number of years the loan is borrowed for. We know that the simple interest is PKR 5400, the rate is 12% p.a., and the time is 3 years. We need to calculate the principal. Substituting the known values into the formula, we get: 5400 = (Principal * 12 * 3) / 100 Multiplying both sides of the equation by 100, we get: 540000 = Principal * 12 * 3 Dividing both sides of the equation by 12 * 3, we get: Principal = 540000 / (12 * 3) Principal = PKR 15000 Therefore, the principal amount borrowed by Kajol was PKR 15000.