alleryStart learning →For the AP $10,\ 7,\ 4,\ \ldots$, the term that first becomes negative is the
A4th term
B6th term
C7th term
D5th term
Answer & Solution
Correct answer: D. 5th term
1. a = 10, d = −3, so $a_n = 10 + (n-1)(-3) = 13 - 3n$.
2. Need $a_n < 0$: $13 - 3n < 0 \Rightarrow n > 4.33$.
3. The smallest such n is 5, so the **5th term** ($a_5 = -2$) is the first negative term.
_Source: Karnataka SSLC (KSEEB) Class 10 Mathematics, Ch1 'Arithmetic Progressions' (nth term inequality)_
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