SAT Math : Arithmetic Sequences

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #7 : Nth Term Of An Arithmetic Sequence

An arithmetic sequence begins as follows:

Give the sixteenth term of this sequence.

Possible Answers:

None of the other responses give the correct answer.

Correct answer:

Explanation:

Subtract the first term  from the second term  to get the common difference :

Setting  and 

The th term of an arithmetic sequence  can be found by way of the formula

Setting , and  in the formula:

Example Question #21 : Arithmetic Sequences

An arithmetic sequence begins as follows: 14, 27, 40...

What is the first four-digit integer in the sequence?

Possible Answers:

Correct answer:

Explanation:

Given the first two terms  and , the common difference  is equal to the difference:

Setting :

The th term of an arithmetic sequence  can be found by way of the formula

Since we are looking for the first four-digit whole number - equivalently, the first number greater than or equal to 1,000:

Setting  and  and solving for :

Therefore, the 77th term, or , is the first element in the sequence greater than 1,000. Substituting , and   in the rule and evaluating:

,

the correct choice.

Example Question #33 : Sequences

Possible Answers:

Correct answer:

Explanation:

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

So,  

Example Question #802 : Arithmetic

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

Possible Answers:

40

32

35

41

37

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 #21 : Arithmetic Sequences

A sequence of numbers is as follows:

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

Possible Answers:

490

621

1529

719

248

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 #1 : How To Find The Next Term In An Arithmetic Sequence

Find the next term of the following sequence:

Possible Answers:

More information is needed

Correct answer:

Explanation:

The sequence provided is arithmetic. An arithmetic sequence has a common difference between each consecutive term. In this case, the difference is ; therefore, the next term is .

You can also use a formula to find the next term of an arithmetic sequence:

where  the current term and  the common difference.

Example Question #5 : How To Find The Next Term In An Arithmetic Sequence

Solve each problem and decide which is the best of the choices given.

 

Find the sixth term in the following arithmetic sequence.

Possible Answers:

Correct answer:

Explanation:

First find the common difference of the sequence,

Thus there is a common difference of

 between each term,

so follow that pattern for another  terms, and the result is .

Example Question #6 : How To Find The Next Term In An Arithmetic Sequence

Find the missing number in the sequence:

Possible Answers:

Correct answer:

Explanation:

The pattern of this sequence is  where  represents the position of the number in the sequence. 

 for the first number in the sequence. 

 for the second number. 

For the fourth term, . Therefore, 

Example Question #4 : How To Find The Next Term In An Arithmetic Sequence

An arithmetic sequence begins as follows:

Express the next term of the sequence in simplest radical form.

Possible Answers:

Correct answer:

Explanation:

Using the Product of Radicals principle, we can simplify the first two terms of the sequence as follows:

The common difference  of an arithmetic sequence can be found by subtracting the first term from the second:

Add this to the second term to obtain the desired third term:

.

Example Question #5 : How To Find The Next Term In An Arithmetic Sequence

An arithmetic sequence begins as follows:

Give the next term of the sequence in simplest radical form.

Possible Answers:

None of the other choices gives the correct response.

Correct answer:

None of the other choices gives the correct response.

Explanation:

Since no perfect square integer greater than 1 divides evenly into 5 or 10, both of the first two terms of the sequence are in simplest form.

The common difference  of an arithmetic sequence can be found by subtracting the first term from the second:

Setting :

Add this to the second term to obtain the desired third term:

This is not among the given choices.

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