Question

Identify a pattern in the given list of numbers. Then use this pattern to find the next number. (More than one pattern might exist, so it is possible that

there is more than one correct answer.)
31, 27, 23, 19, 15,

Answer 1

• pattern: numbers decrease by 4
• next number: 11

Explanation:

You want the next number in the sequence 31, 27, 23, 19, 15, ... such that it follows the same pattern.

Sequence patterns

It is often useful to look at the differences between successive terms of a sequence. This can quickly reveal a pattern if the sequence is polynomial or exponential.

Here, the differences are ...

27 -31 = -4

23 -27 = -4

19 -23 = -4

15 -19 = -4

It appears reasonable to assume that the pattern is that each term is 4 less than the previous one.

Next term

The number that is 4 less than 15 is ...

15 -4 = 11

The next number in the pattern is 11.