question_answer

Sum of n terms of the series \[\sqrt{\mathbf{80}}\mathbf{,}\sqrt{\mathbf{45}}\mathbf{,}\sqrt{\mathbf{20}}\mathbf{,}.......\] is ______

A) \[\frac{\sqrt{5n}}{2}(9-n)\]         

B) \[4\sqrt{5}(9-n)\]

C) \[2\sqrt{5}(9-n)\]  

D)                                                        \[3\sqrt{5}(3-n)\]

E) None of these