Answer:
f(5) = 20
f(6) = 40
Explanation:
The
term of a GP is given by:

where 'a' is the first term and
'r' is the common difference.
It is given that f(3) = 5 and f(4) = 10

and
.
Dividing them we get:


i.e, Common difference, r = 2
Now,
20
Similarly,
40
Hence, the answer.