The difference between simple and compound interests compounded annually on a certain sum of money for 2 years at 18% per annum is Rs 81. The sum is ____.
Of three positive numbers, the ratio of first and second is 5 : 2, ratio of second and third is 5 : 4. The product of first and third is 1800. What is the sum of the three numbers?
Two trains, one 150 m long and the other 130m long, coming from opposite directions crosssed each other in 7.2 seconds. The sum of speed of the two trains every hour would then be