Problem 13 of 34fun-013
The first three terms of an arithmetic sequence are , and . What is the 20th term of the sequence?
Try it first
The walkthrough opens once you check an answer.
Solution walkthrough1:29
- An arithmetic sequence adds the same number each time. Here and .
- Every term is the first term, , plus some steps of . The 5th term has 4 steps.
- So term is . The 20th term has steps of .
- , and .
- Traps: leaves out the first term, uses 20 steps instead of 19, and is .