# Puzzle and tricking

#### Funkj

##### New member
Among 120 , 115, 105, 90, 70, 50 and 15, which one doesn't suit the group.... Please I need answer and explanation

#### mmm4444bot

##### Super Moderator
Staff member
Hello Funkj. Please complete the request to read the forum guidelines, and then let us know what you've thought about or tried so far. Thanks!

#### JeffM

##### Elite Member
This kind of question usually does not have a single correct answer. It is merely an exercise in recognizing possible patterns. So I shall give you three.

15 does not fit in the group because all the rest exceed 40.

120 does not fit in the group because all the rest are smaller than 119.

120 does not fit because all the rest are not evenly divisible by 4.

This kind of question essentialy involves guessing what the questioner expects as an answer.

#### Otis

##### Senior Member
… Please I need answer and explanation
Is this homework? If so, what topics have been discussed in class recently?

I see other possible answers that involve prime factors.

#### Subhotosh Khan

##### Super Moderator
Staff member
Among 120 , 115, 105, 90, 70, 50 and 15, which one doesn't suit the group.... Please I need answer and explanation
As you saw it can be almost any number!

But I think it is 50. I'll leave the explanation to you.

#### Dr.Peterson

##### Elite Member
Among 120 , 115, 105, 90, 70, 50 and 15, which one doesn't suit the group.... Please I need answer and explanation
The pattern I see becomes visible if you list the differences between successive numbers and look for a progression.

Another that I find less interesting involves powers of a prime factor. This gives the same answer for an entirely unrelated reason.

But unless someone defines "the group" for you, the question is one of creativity, not truth.