PSAT Math : How to find the next term in an arithmetic sequence

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #21 : Arithmetic Sequences

Possible Answers:

Correct answer:

Explanation:

Each term in the sequence is one less than twice the previous term.

So,  

Example Question #31 : Sequences

What is the next number in the following series: 0, 3, 8, 15, 24 . . . ?

Possible Answers:

40

32

37

41

35

Correct answer:

35

Explanation:

The series is defined by n2 – 1 starting at n = 1. The sixth number in the series then equal to 62 – 1 = 35.

Example Question #31 : Sequences

A sequence of numbers is as follows:

What is the sum of the first seven numbers in the sequence?

Possible Answers:

1529

248

490

719

621

Correct answer:

621

Explanation:

The pattern of the sequence is (x+1) * 2.

We have the first 5 terms, so we need terms 6 and 7:

(78+1) * 2 = 158

(158+1) * 2 = 318

3 + 8 + 18 +38 + 78 + 158 + 318 = 621

Example Question #181 : Integers

Find the  term in the sequence

Possible Answers:

Correct answer:

Explanation:

Notice that in the sequence 

each term increases by .

It is always good strategy when attempting to find a pattern in a sequence to examine the difference between each term.

We continue the pattern to find:

The  term is 

The  term is 

The  term is 

It is useful to note that the sequence is defined by,

where n is the number of any one term.

We can solve

to find the  term.

 

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