Answer:
292,968
Step-by-step explanation:
As we know,
Sum of a geometric sequence (S) = 
where,
a = first term of sequence,
r = the constant ratio,
n = number of terms in sequence.
So, according to the question,
a = 3,
r = 5,
n = 8.
by substituting the values in the above formula, we get;
⇒ 
⇒ 