Question

* The nth term of sequence A is 3n − 2 The nth term of sequence B is 10 − 2n Sally says there is only one number that is in both sequence A and sequence B. Is Sally right? You must explain your answer.

Answer 1

Answer:

Sally is not right

Step-by-step explanation:

Given the two sequences which have their respective $n^{th}$ terms as following:

Sequence A. $3n - 2$

Sequence B. $10 - 2n$

As per Sally, there exists only one number which is in both the sequences.

To find:

Whether Sally is correct or not.

Solution:

For Sally to be correct, we need to put the $n^{th}$ terms of the respective sequences as equal and let us verify that.

$3n-2=10-2n\\\Rightarrow 3n+2n=10+2\\\Rightarrow 5n=12\\\Rightarrow n = \dfrac{12}{5}$

When we talk about $n^{th}$ terms, $n$ here is a whole number not a fractional number.

But as per the statement as stated by Sally $n$ is a fractional number, only then the two sequences can have a number which is in the both sequences.

Therefore, no number can be in both the sequences A and B.

Hence, Sally is not right.