B1=8748 n=7 bn=12 Sn-? q-?

Question

B1=8748 n=7 bn=12 Sn-? q-?

Answer 1

Bn=b1*g^(n-1)
12=8748*g^(7-1)
g^6=12/8748
g^6=1/729
g=1/3
Sn=(b1- bn*g)/(1-g)
Sn=(8748-12*1/3)/(1-1/3)
Sn=(8748-4)/2*3
Sn=8744*3/2
Sn=13116