
If 7 times the seventh term of an Arithmetic Progression (AP) is equal to 11 times its eleventh term, then the 18th term of the AP will be
A. 0 B. 1 C. 2 D. -1 Answer: Option AShow Answer
Solution(By Apex Team)
Let the first term of the AP be a and the common difference = d
7th term = A7 = a + 6d
11th term = A11 = a + 10d
According to question,
$\begin{array}{l}\Rightarrow7\times(a+6d)=11\times(a+10d)\\
\Rightarrow7a+42d=11a+110d\\
\Rightarrow11a-7a=42d-110d\\
\Rightarrow4a=-68d\\
\Rightarrow a=-17d\\
\Rightarrow a+17d=0=A_{18}\end{array}$
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