# Recent questions tagged arithmetic-series

1
The sum of the series $\:3+11+\dots +(8n-5)\:$ is $4n^2-n$ $8n^2+3n$ $4n^2+4n-5$ $4n^2+2$
2
If $l=1+a+a^2+ \dots$, $m=1+b+b^2+ \dots$, and $n=1+c+c^2+ \dots$, where $\mid a \mid <1, \: \mid b \mid < 1, \: \mid c \mid <1$ and $a,b,c$ are in arithmetic progression, then $l, m, n$ are in arithmetic progression geometric progression harmonic progression none of these
3
If the sum of the first $n$ terms of an arithmetic progression is $cn^2$, then the sum of squares of these $n$ terms is $\frac{n(4n^2-1)c^2}{6}$ $\frac{n(4n^2+1)c^2}{3}$ $\frac{n(4n^2-1)c^2}{3}$ $\frac{n(4n^2+1)c^2}{6}$
1 vote
4
The sequence $\dfrac{1}{\log_3 2}, \: \dfrac{1}{\log_6 2}, \: \dfrac{1}{\log_{12} 2}, \: \dfrac{1}{\log_{24} 2} \dots$ is in Arithmetic progression (AP) Geometric progression ( GP) Harmonic progression (HP) None of these
5
If $x,y,z$ are in $A.P.$ and $a>1$, then $a^x, a^y, a^z$ are in $A.P.$ $G.P$ $H.P$ none of these
6
If $a,b,c$ are in $A.P.$ , then the straight line $ax+by+c=0$ will always pass through the point whose coordinates are $(1,-2)$ $(1,2)$ $(-1,2)$ $(-1,-2)$
7
If the co-efficient of $p^{th}, (p+1)^{th}$ and $(p+2)^{th}$ terms in the expansion of $(1+x)^n$ are in Arithmetic Progression (A.P.), then which one of the following is true? $n^2+4(4p+1)+4p^2-2=0$ $n^2+4(4p+1)+4p^2+2=0$ $(n-2p)^2=n+2$ $(n+2p)^2=n+2$
8
The sum of $n$ terms of the series $4+44+444+ \dots \dots$ is $\frac{4}{81}\left[10^{n+1}-9n-1\right]$ $\frac{4}{81}\left[10^{n-1}-9n-1\right]$ $\frac{4}{81}\left[10^{n+1}-9n-10\right]$ $\frac{4}{81}\left[10^{n}-9n-10\right]$
How many integers are there between $100$ and $1000$ all of whose digits are even? $60$ $80$ $100$ $90$
If the list of letters $P$, $R$, $S$, $T$, $U$ is an arithmetic sequence, which of the following are also in arithmetic sequence? $2P, 2R, 2S, 2T, 2U$ $P-3, R-3, S-3, T-3, U-3$ $P^2, R^2, S^2, T^2, U^2$ I only I and II II and III I and III
What will be the maximum sum of $44, 42, 40, \dots$ ? $502$ $504$ $506$ $500$