Posted by Anonymous on .
The sun of the first five terms of a geometric series is 186 and the sum of the first six terms is 378. if the fourth term is 48, determine a,r, t10, S10

FUNCTION 11..HELP! 
PJ,
The sun of the first five terms of a geometric series is 186 and the sum of the first six terms is 378. if the fourth term is 48, determine a,r, t10, S10

FUNCTION 11..HELP! 
Steve,
Since S6 = S5 + T6,
378 = 186 + T6
T6 = 192
T6 = T4*r^2
192 = 48r^2
r^2=4
r=2
T4 = ar^3
48 = 8a
a = 6
Sequence is thus
6, 12, 24, 48, 96, 192, ...
T10 = 6*2^9 = 3072
S10 = 6*(1023) = 6138