Question

The first three terms of a sequence are given. Write your answer as a decimal or whole number. Round to the nearest thousandth (if necessary).
260, comma, 255, comma, 250, comma, dot dot dot
260,255,250,...
Find the 43rd term.

Answers

GPT-4o mini
To find the 43rd term of the sequence given by 260, 255, 250, ..., we first observe the pattern in the sequence.

The first three terms are:
- 1st term: 260
- 2nd term: 255
- 3rd term: 250

We can see that each term decreases by 5 from the previous term. This indicates that the sequence is an arithmetic sequence with the first term \( a = 260 \) and a common difference \( d = -5 \).

The formula for the \( n \)-th term of an arithmetic sequence is given by:
\[
a_n = a + (n-1)d
\]

We want to find the 43rd term (\( n = 43 \)):
\[
a_{43} = 260 + (43 - 1)(-5)
\]
\[
a_{43} = 260 + 42 \times (-5)
\]
\[
a_{43} = 260 - 210
\]
\[
a_{43} = 50
\]

Thus, the 43rd term of the sequence is \( \boxed{50} \).

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