A farmer's land is in the shape of a trapezium which has its parallel sides measuring 2.56 yards and 3.44 yards and the distance between the parallelsides in 1.44 yards. The cost of ploughing the land is Rs 1800 per square yard. What amount will (in Rs) have to be spent in order to plough the entire land?

Pabitra had$19\frac{2}{7}$ l of petrol in the fuel tank of his vehicle at the start of a journey. During the journey,$13\frac{1}{2}$ l of petrol was consumed. What fraction of the initial petrol was left in the fuel tank after the journey?

The sum of the squares of 3 natural numbers is 1029, and they are in the proportion 1 : 2 : 4. The difference between greatest number and smallest number is: