Asked by Kaycee
For the series 16, 24, 36, 54,... find S7.
A) 32.17
B) 115.75
C) 514.75
D) 3906.25
B?
A) 32.17
B) 115.75
C) 514.75
D) 3906.25
B?
Answers
Answered by
Reiny
looks like a GP with a = 16, and r = 3/2
sum(7) = a( r^7 - 1)/(r-1)
= 16(2187/128) - 1)/(1/2)
= 32(2059/128)
= 2059/4 or 514.75
how can the answer be 115.75 when the first 4 terms shown already add up to 130 ?
Are you just guessing ?
sum(7) = a( r^7 - 1)/(r-1)
= 16(2187/128) - 1)/(1/2)
= 32(2059/128)
= 2059/4 or 514.75
how can the answer be 115.75 when the first 4 terms shown already add up to 130 ?
Are you just guessing ?