Question

What is the common ratio of the sequence 3, 21, 147, … ?

Answer 1

1029 the sequence increases by multiples of 7.

Answer 2

Common ratio = 7

Explanation:

If a sequence is a geometric sequence, given in the form of a, a(r), a(r)² ..........

common ratio of the given sequence will be =
`(ar)/(a)=r`

Now we apply this rule in the given sequence 3, 21, 147,.............

Then the common ratio r =
`\frac{\text{Second term}}{\text{First term}}`

r =
`(21)/(3)`

r = 7

This can be applied in 2nd and 3rd term but common ratio will remain same as 7.

Therefore, common ratio = 7 is the answer.