Question

If the sixth term of a sequence is 128 and the common ratio is 2, then what is the first term?

1
2
4

Answer 1

Hello,

Answer C: 4


`u_(6)=128`

`u_(5)=64`

`u_(4)=32`

`u_(3)=16`

`u_(2)=8`

`u_(1)=4`

Answer 2

Answer: The first term of the sequence is 4.

Explanation:

Let a be the first term of the sequence,

Here, the common ratio of the sequence is 2,

Thus, the sequence is,

a, 2a, 4a, 8a, 16a, 32a, .............., so on,...

Since, the sixth term of the sequence = 32a

According to the question,

32 a = 128

⇒ a = 4

Thus, the first term of the sequence is 4.