question_answer

Consider an infinite geometric series with first term a and common ratio r. If its sum is 4 and the second term is\[\frac{3}{4},\] then which one of the following can be true?

A)  \[a=\frac{4}{7},\,r=\frac{3}{7}\]                     

B)  \[a=2,\,r=\frac{3}{8}\]

C)  \[a=\frac{3}{2},\,r=\frac{1}{2}\]                     

D)  \[a=3,\,r=\frac{1}{4}\]

E)  None of these