question_answer

A bird flies 'n' km one way. Which of the following expressions shows 2 round trips? (Remember that a round trip is a trip to a place and back to the starting place.)            

A)              \[\text{(4}-\text{n) km}\]                             

B)              \[(\text{2}-\text{n) km}\]          

C)              \[\text{(2n) km}\]          

D)                                        \[\text{(4n) km}\]