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An arithmetic progression is written in the following way
The sum of all the terms of the $10^{\text {th }}$ row is_______
The sum of all the terms of the $10^{\text {th }}$ row is_______
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The correct answer is:
1505
$\begin{aligned} & 2,5,11,20, \ldots . . \\ & \text { General term }=\frac{3 n^2-3 n+4}{2} \\ & \begin{aligned} & \mathrm{T}_{10}=\frac{3(100)-3(10)+4}{2} \\ & \quad= 137 \\ & 10 \text { terms with c.d. }=3 \\ & \text { sum }=\frac{10}{2}(2(137)+9(3)) \\ &=1505\end{aligned}\end{aligned}$
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