the 8 term of g.p is 640 and the first terms is 5 find the common ratio and 10 terms
5r^7 = 640
r^7 = 128
r = 2
Now find as many terms as you want.
S10 = a(r^10 - 1)/(r-1)
r^7 = 128
r = 2
Now find as many terms as you want.
S10 = a(r^10 - 1)/(r-1)