Question

if the 5 th term of gp is 16 and 10th term is 1/2 then the 15th term is​

Answer 1

a5=a+(n-1)d

16=a+4d

a10=a+9d

1=2a+18d

a+4d=16 ×(2)

2a+18d=1 ×(1)

2a+8d=32

2a+18d=1

(-). (-). (-)

________

-10d=31

d=-3.1

a+12.4=16

a=3.6

a15=3.6+14×3.1

=3.6-43.4

39.8