SAT Math : How to find the nth term of an arithmetic sequence

Study concepts, example questions & explanations for SAT Math

varsity tutors app store varsity tutors android store varsity tutors amazon store varsity tutors ibooks store

Example Questions

2 Next →

Example Question #31 : 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.

2 Next →
Learning Tools by Varsity Tutors