If the sum and product of the first three term in an A.P. are 33 and 1155, respectively, then a value of its 11th term is :

Question

If the sum and product of the first three term in an A.P. are 33 and 1155, respectively, then a value of its 11th term is : (A) -25 (B) 25 (C) -36 (D) -35

Tardigrade Admin · Accepted Answer

a - d + a + a + d = 33 ⇒ a = 11 a(a2 - d2) = 1155 121 - d2 = 105 d2 = 16 ⇒ d = ± 4 If d = 4 then Ist term = 7 If d = -4 then Ist term = 15 T11 = 7 + 40 = 47

Q. If the sum and product of the first three term in an $A . P$ . are $33$ and $1155$ , respectively, then a value of its $1 1^{t h}$ term is :

-25

25

-36

-35

$a - d + a + a + d = 33$ $\Rightarrow$ $a = 11$
$a (a^{2} - d^{2}) = 1155$
$121 - d^{2} = 105$
$d^{2} = 16 \Rightarrow d = \pm 4$
If $d = 4$ then Ist term = $7$
If $d = - 4$ then Ist term = $15$
$T_{11} = 7 + 40 = 47$

Q. If the sum and product of the first three term in an A.P. are 33 and 1155, respectively, then a value of its 11th term is :

-25

25

-36

-35

a−d+a+a+d=33 ⇒ a=11 a(a2−d2)=1155 121−d2=105 d2=16⇒d=±4 If d=4 then Ist term = 7 If d=−4 then Ist term = 15 T11​=7+40=47

Q. If the sum and product of the first three term in an $A . P$ . are $33$ and $1155$ , respectively, then a value of its $1 1^{t h}$ term is :

$a - d + a + a + d = 33$ $\Rightarrow$ $a = 11$
$a (a^{2} - d^{2}) = 1155$
$121 - d^{2} = 105$
$d^{2} = 16 \Rightarrow d = \pm 4$
If $d = 4$ then Ist term = $7$
If $d = - 4$ then Ist term = $15$
$T_{11} = 7 + 40 = 47$