How do you find the common ratio for #7,14,28,56,128,...#?

1 Answer
Jul 24, 2016

Answer:

Ignoring the #128# (which should probably have been #112#), the common ratio is #2#.

Explanation:

For this sequence to have a common ratio, the ratio between any pair of consecutive terms must be the same.

So if this sequence does have a common ratio, then we can look at any pair of consecutive terms, e.g. #7, 14# to find the ratio:

#14/7 = 2#

This ratio is the same for #28/14# and #56/28#, but #128 != 2*56#.

I suspect a typo in the question. The value you would expect is #112# rather than #128#.