Mathematics - Sequence & Series Question with Solution | TestHub

All terms of an A.P. are natural numbers. The sum of its first nine terms lies between 200 and 220 . If the second term is 12 , then first term is

$$\begin{array}{rlr}& 200<\frac{9}{2}(2(12-d)+8d)<220& \Rightarrow d=4\end{array}$$

∴ First term $=12-\mathrm{d}=8$