question_answer

The value of\[(5\,{{a}^{6}})\,\,\times \,\,(-\,10a{{b}^{2}})\,\,\times \,\,(2.1\,{{a}^{2}}{{b}^{3}})\] for \[a=1\]and \[b\frac{1}{2}\]is:

A)  \[-\frac{105}{32}\]       

B)  \[\frac{105}{64}\]

C)  \[\frac{150}{32}\]                                

D)  1

E)  None of these