A migrating bird flies 40 km North, then turns East and flies 50 km, then turns North and flies 110 km, and turns to its left and flies 50 km. Where is it now with reference to its starting position?
In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?
The weights of 4 boxes are 90, 30, 20 and 50 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?