a1, a5, a13 (terms of AP) are in GP and a6 + a15 =63. Find a23 Choose the correct choice:
A) 181/3
B) 182/3
C) 183/3
D) 184/3
E) 182/5
a1   a5= a1+ 4d   a13= a1+12d   Now a5/a1 = a13/a5----&gt;&gt;a1=4d........(1)   Given a6 + a15=63   ----&gt; a1+5d + a1+14d=63   ----&gt;2a1+ 19d = 63   ----&gt;8d+ 19d=63 from (1)   ----&gt; d=63/27= 7/3   so a=4d=4*7/3=28/3 from (1)   a23= a1+ 22d =28/3 +22*7/3   =182/3   ANSWER:182/3
<result>B</result>
a1, a5, a13 (terms of AP) are in GP and a6 + a15 =63. Find a23