In a row of boys, Amit is ranked 12th from top and Ratan is 15th from bottom. They interchange their position. Ratan now becomes 37th from bottom. How many total boys are there in the row?
The weights of 4 boxes are 20, 40, 60 and 90 kilograms. Which of the following cannot be the total weight, in kilograms, of any combination of these boxes and in a combination a box can be used only once?
In a certain code language, '-' represents '+', '+' represents 'x', 'x' represents '÷' and '÷' represents '-'. Find out the answer to the following question.
In this question, some equations are solved on the basis of a certain system. On the same basis find out the correct answer from amongst the four alternatives for the unsolved equation.