Question

What is the 10th term of the geometric sequence 400, 200, 100…?

Answer 1

1. B

2. A

3. C

4. A

5. B

6. C

7. B

Skip, 8,9,12,13,14

10. A

11. C

Answer 2

Answer:  The correct option is (C). 0.78125.

Step-by-step explanation:  We are given to find the 10th term of the following geometric sequence

400,  200,  100, . . . .

We know that,

the n-th term of a geometric sequence with first term a and common ration r is given by

$a_n=ar^{n-1}.$

In the given sequence,

first term, a = 400

and

common ration is given by

$r=\dfrac{200}{400}=\dfrac{100}{200}=~.~.~.~=0.5.$

Therefore, the 10th term of the sequence is

$a_{10}= ar^{10-1}=400\times (0.5)^9=400\times0.001953125=0.78125.$

Thus, the correct option is (C). 0.78125.