Praxis Core Academic Skills for Educators: Mathematics (5733)Algebra and FunctionsEasy
A botanist observes that the number of leaves on a particular plant follows a pattern. The first leaf appears on day 5, the second on day 8, and the third on day 11. If this pattern continues, on what day will the 8th leaf appear?
- ADay 26
- BDay 23
- CDay 32
- DDay 29
Show answer & explanationAnswer & explanation
Correct answer: A. Day 26
This is an arithmetic sequence where the first term is 5 and the common difference is 3. Using the formula a_n = a_1 + (n-1)d, we can find the 8th term.
Why the other options are wrong
- B. This would be the result if the common difference was 2, or if there was a calculation error.
- C. This would be an error in calculating the common difference or applying the formula.
- D. This might result from incorrectly using n as 7 or 9 in the formula, or a different common difference.
Arithmetic Sequence
A sequence of numbers such that the difference between consecutive terms is constant.
- Common difference (d) is constant.
- Formula: a_n = a_1 + (n-1)d
- Used to find any term in the sequence.
Memory trick: Think of an arithmetic sequence like steps on a ladder, each one a consistent height above the last.