If the sum of three numbers in $A.P.,$ is $24$ and their product is $440,$ find the numbers.
Let the three numbers in $A.P.$ be $a-d, a,$ and $a+d$
According to the given information,
$(a-d)+(a)+(a+d)=24$ .........$(1)$
$\Rightarrow 3 a=24$
$\therefore a=8$
$(a-d) a(a+d)=440$ .........$(2)$
$\Rightarrow(8-d)(8)(8+d)=440$
$\Rightarrow(8-d)(8+d)=55$
$\Rightarrow 64-d^{2}=55$
$\Rightarrow d^{2}=64-55=9$
$\Rightarrow d^{2}=\pm 3$
Therefore, when $d=3,$ the numbers are $5,8$ and $11$ and when $d=-3,$ the numbers are $11,8$ and $5$
Thus, the three numbers are $5,8$ and $11 .$
If the sum and product of the first three term in an $A.P$. are $33$ and $1155$, respectively, then a value of its $11^{th}$ tern is
The ratio of the sums of first $n$ even numbers and $n$ odd numbers will be
The arithmetic mean of first $n$ natural number
If ${S_1},\;{S_2},\;{S_3},...........{S_m}$ are the sums of $n$ terms of $m$ $A.P.'s$ whose first terms are $1,\;2,\;3,\;...............,m$ and common differences are $1,\;3,\;5,\;...........2m - 1$ respectively, then ${S_1} + {S_2} + {S_3} + .......{S_m} = $
Insert $6$ numbers between $3$ and $24$ such that the resulting sequence is an $A.P.$