GEOMETRIC SERIES

Find the sum of 125 + 25 + 5 +... + S₉

• $\frac{488280}{3125}$

• $\frac{488281}{3125}$

• $\frac{3125}{488280}$

• $\frac{3125}{488281}$

The expression formed by adding the terms of a geometric sequence is called _______

• Geometric sequence

• Geometric means

• Geometric series

• Common ratio

In geometric series if r = -1, and n is odd number, then the sum of its geometric sequence is equal to

• 0

• its first term

• 1

• its common ratio

Find the sum of the first 6 terms of a geometric sequence -336, 84, -21, ...

• $\frac{-17199}{64}$

• $\frac{64}{17199}$

• $\frac{-64}{17199}$

• $\frac{17199}{64}$

In geometric sequence if r = -1 and n is even number , then the sum is equal to

• 0

• 1

• its first term

• its common ratio

What is the common ratio in the sequence

 $2\sqrt{x},\ 6\sqrt{x},\ 18\sqrt{x},\ ...$  ?

• 2

•  $\sqrt{x}$  

•  $3\sqrt{x}$  
  

• 3

What is the sum of the first 7 terms of a geometric sequence 4, 2, 1, ...?

• $\frac{16}{127}$

• $\frac{127}{16}$

• 16

• 127

9 + 6 + 4 + ..., the find S₇

• $\frac{2059}{81}$

• $-\frac{2059}{81}$

• $-\frac{81}{2059}$

• $\frac{81}{2059}$

Find the sum of the first 10 terms of a geometric sequence 5, 10, 20, ...

• 5115

• 5114

• 5113

• 5112

A culture initially contains 200 bacteria. If the number of bacteria doubles every 2 hours, how many bacteria will be in the culture at the end of 12 hours?

• 12400

• 12500

• 12600

• 12700