What is the fifth term of a sequence whose first term is 5 and whose common ratio is 3?

A.243
B.405
C.1,215

Question

What is the fifth term of a sequence whose first term is 5 and whose common ratio is 3? 

A.243
B.405
C.1,215

asnaseer · Answer

you just asked and closed this question here: http://openstudy.com/updates/4fe6279ee4b02c91101afdf1

asnaseer · Answer

please don't close and repost the same questions - it is considered spamming and may lead to suspension.

zepp · Answer

This is a geometric sequence with first term 5; common ratio 3.

Mean that
1st term
2nd term = 1st term * 3
3rd term = 2nd term * 3
...
and so on.

zepp · Answer

And to find any term, use the rule $x = ar^{n-1}$ where n is the term you are trying to find.

campbell_st · Answer

a term in a geometric series is found using

$$T _{n} = ar^{n -1}$$

you have a = 5, r = 3 and n = 5

$$T _{5} = 5\times 3^{5 -1}$$

just evaluate

zepp · Answer

We are looking for the 5th term, plug replace a by 5; r by 3; n by 5 and solve for x;

$\large x = 5*3^{5-1}=5*3^4=405$