Question

plz help to solve this problem

Answer 1

acc to question 

fifth term of ap=3(2nd term of ap)
a+4d=3(a+d)
2a-d=0                                                  ...1
also 
twelfth term of ap=2(6th term of ap)+1
a+11d=2(a+5d)+1
a-d=-1                                                   ...2
from 1 and 2
a=1 and d=2
then 16th term=a+15d
                       =1+15(2)
                       =1+30=31

   :):):)hope this ans would help u..