A sum of money was invested at simple interest at a certain rate for 5 years. Had it been invested at a 5% higher rate, it would have fetched ₹500 more. What was the principal amount?
The difference between the compound interest (compounded annually) and the simple interest on a certain sum of money at 12% per annum for 2 years is ₹72. What is the principal amount?
Walking at \( \frac{4}{5} \)th of his usual speed, a man is 12 minutes late for his office. What is the usual time taken by him to cover that distance?
In a mixture of 80 litres of a liquid and water, 25% of the mixture is the liquid. How much water should be added to the mixture so that the liquid becomes 20% of the mixture?
Let the work done by \( (x - 1) \) men in \( (x + 1) \) days be \( y \). Let the work done by \( (x + 2) \) men in \( (x - 1) \) days be \( z \). If \( y : z = 9 : 10 \), then what is the value of \( x \)?
