Geometric Progression
Sequence and Series

118680 The arithmetic mean of the series \(1,2,4,8\), \(16, \ldots . ., 2^{\mathrm{n}}\) is
#[Qdiff: Very Easy, QCat: Theory Based, examname: SRM JEEE-2011]\(\therefore \text { Required mean }=\frac{1+2+4+8+\ldots .+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{2^0+2^1+2^2+\ldots \ldots+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{1\left(\frac{2^{n+1}-1}{2-1}\right)}{n+1}\)
, \({\left[\because 2^0, 2^1, 2^2, \ldots \ldots 2^{\text {n }} \text { is a G.P. }\right]}\)
, \(=\frac{2^{n+1}-1}{n+1}\)]#

1 \(\frac{2^{\mathrm{n}}-1}{\mathrm{n}}\)
2 \(\frac{2^{\mathrm{n}+1}-1}{\mathrm{n}+1}\)
3 \(\frac{2^{\mathrm{n}}+1}{\mathrm{n}}\)
4 none of these
Sequence and Series

118673 If the 9th term of an AP is zero, then the ratio of 29 th term to 19 th term is

1 \(1: 2\)
2 \(1: 3\)
3 \(2: 1\)
4 \(3: 1\)
5 \(9: 1\)
Sequence and Series

118665 A arithmetic mean progression of two numbers is 6 more than the geometric mean progression of the numbers. The ratio of number is \(9: 1\), then numbers are

1 27,3
2 16,3
3 15,4
4 None of these
Sequence and Series

118666 If \(a, b\) and \(c\) are in HP, then for any \(n \in N\), which one of the following is true?

1 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}\lt 2 \mathrm{~b}^{\mathrm{n}}\)
2 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}>2 \mathrm{~b}^{\mathrm{n}}\)
3 \(a^n+c^n=2 b^n\)
4 None of the above
Sequence and Series

118667 If the sum of four numbers in GP is 60 and the arithmetic mean of the first and last numbers is 18 , then the numbers are

1 \(3,9,27,81\)
2 \(4,8,16,32\)
3 2, 6, 18, 54
4 None of these
Sequence and Series

118680 The arithmetic mean of the series \(1,2,4,8\), \(16, \ldots . ., 2^{\mathrm{n}}\) is
#[Qdiff: Very Easy, QCat: Theory Based, examname: SRM JEEE-2011]\(\therefore \text { Required mean }=\frac{1+2+4+8+\ldots .+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{2^0+2^1+2^2+\ldots \ldots+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{1\left(\frac{2^{n+1}-1}{2-1}\right)}{n+1}\)
, \({\left[\because 2^0, 2^1, 2^2, \ldots \ldots 2^{\text {n }} \text { is a G.P. }\right]}\)
, \(=\frac{2^{n+1}-1}{n+1}\)]#

1 \(\frac{2^{\mathrm{n}}-1}{\mathrm{n}}\)
2 \(\frac{2^{\mathrm{n}+1}-1}{\mathrm{n}+1}\)
3 \(\frac{2^{\mathrm{n}}+1}{\mathrm{n}}\)
4 none of these
Sequence and Series

118673 If the 9th term of an AP is zero, then the ratio of 29 th term to 19 th term is

1 \(1: 2\)
2 \(1: 3\)
3 \(2: 1\)
4 \(3: 1\)
5 \(9: 1\)
Sequence and Series

118665 A arithmetic mean progression of two numbers is 6 more than the geometric mean progression of the numbers. The ratio of number is \(9: 1\), then numbers are

1 27,3
2 16,3
3 15,4
4 None of these
Sequence and Series

118666 If \(a, b\) and \(c\) are in HP, then for any \(n \in N\), which one of the following is true?

1 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}\lt 2 \mathrm{~b}^{\mathrm{n}}\)
2 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}>2 \mathrm{~b}^{\mathrm{n}}\)
3 \(a^n+c^n=2 b^n\)
4 None of the above
Sequence and Series

118667 If the sum of four numbers in GP is 60 and the arithmetic mean of the first and last numbers is 18 , then the numbers are

1 \(3,9,27,81\)
2 \(4,8,16,32\)
3 2, 6, 18, 54
4 None of these
Sequence and Series

118680 The arithmetic mean of the series \(1,2,4,8\), \(16, \ldots . ., 2^{\mathrm{n}}\) is
#[Qdiff: Very Easy, QCat: Theory Based, examname: SRM JEEE-2011]\(\therefore \text { Required mean }=\frac{1+2+4+8+\ldots .+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{2^0+2^1+2^2+\ldots \ldots+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{1\left(\frac{2^{n+1}-1}{2-1}\right)}{n+1}\)
, \({\left[\because 2^0, 2^1, 2^2, \ldots \ldots 2^{\text {n }} \text { is a G.P. }\right]}\)
, \(=\frac{2^{n+1}-1}{n+1}\)]#

1 \(\frac{2^{\mathrm{n}}-1}{\mathrm{n}}\)
2 \(\frac{2^{\mathrm{n}+1}-1}{\mathrm{n}+1}\)
3 \(\frac{2^{\mathrm{n}}+1}{\mathrm{n}}\)
4 none of these
Sequence and Series

118673 If the 9th term of an AP is zero, then the ratio of 29 th term to 19 th term is

1 \(1: 2\)
2 \(1: 3\)
3 \(2: 1\)
4 \(3: 1\)
5 \(9: 1\)
Sequence and Series

118665 A arithmetic mean progression of two numbers is 6 more than the geometric mean progression of the numbers. The ratio of number is \(9: 1\), then numbers are

1 27,3
2 16,3
3 15,4
4 None of these
Sequence and Series

118666 If \(a, b\) and \(c\) are in HP, then for any \(n \in N\), which one of the following is true?

1 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}\lt 2 \mathrm{~b}^{\mathrm{n}}\)
2 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}>2 \mathrm{~b}^{\mathrm{n}}\)
3 \(a^n+c^n=2 b^n\)
4 None of the above
Sequence and Series

118667 If the sum of four numbers in GP is 60 and the arithmetic mean of the first and last numbers is 18 , then the numbers are

1 \(3,9,27,81\)
2 \(4,8,16,32\)
3 2, 6, 18, 54
4 None of these
Sequence and Series

118680 The arithmetic mean of the series \(1,2,4,8\), \(16, \ldots . ., 2^{\mathrm{n}}\) is
#[Qdiff: Very Easy, QCat: Theory Based, examname: SRM JEEE-2011]\(\therefore \text { Required mean }=\frac{1+2+4+8+\ldots .+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{2^0+2^1+2^2+\ldots \ldots+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{1\left(\frac{2^{n+1}-1}{2-1}\right)}{n+1}\)
, \({\left[\because 2^0, 2^1, 2^2, \ldots \ldots 2^{\text {n }} \text { is a G.P. }\right]}\)
, \(=\frac{2^{n+1}-1}{n+1}\)]#

1 \(\frac{2^{\mathrm{n}}-1}{\mathrm{n}}\)
2 \(\frac{2^{\mathrm{n}+1}-1}{\mathrm{n}+1}\)
3 \(\frac{2^{\mathrm{n}}+1}{\mathrm{n}}\)
4 none of these
Sequence and Series

118673 If the 9th term of an AP is zero, then the ratio of 29 th term to 19 th term is

1 \(1: 2\)
2 \(1: 3\)
3 \(2: 1\)
4 \(3: 1\)
5 \(9: 1\)
Sequence and Series

118665 A arithmetic mean progression of two numbers is 6 more than the geometric mean progression of the numbers. The ratio of number is \(9: 1\), then numbers are

1 27,3
2 16,3
3 15,4
4 None of these
Sequence and Series

118666 If \(a, b\) and \(c\) are in HP, then for any \(n \in N\), which one of the following is true?

1 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}\lt 2 \mathrm{~b}^{\mathrm{n}}\)
2 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}>2 \mathrm{~b}^{\mathrm{n}}\)
3 \(a^n+c^n=2 b^n\)
4 None of the above
Sequence and Series

118667 If the sum of four numbers in GP is 60 and the arithmetic mean of the first and last numbers is 18 , then the numbers are

1 \(3,9,27,81\)
2 \(4,8,16,32\)
3 2, 6, 18, 54
4 None of these
Sequence and Series

118680 The arithmetic mean of the series \(1,2,4,8\), \(16, \ldots . ., 2^{\mathrm{n}}\) is
#[Qdiff: Very Easy, QCat: Theory Based, examname: SRM JEEE-2011]\(\therefore \text { Required mean }=\frac{1+2+4+8+\ldots .+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{2^0+2^1+2^2+\ldots \ldots+2^{\mathrm{n}}}{\mathrm{n}+1}\)
, \(=\frac{1\left(\frac{2^{n+1}-1}{2-1}\right)}{n+1}\)
, \({\left[\because 2^0, 2^1, 2^2, \ldots \ldots 2^{\text {n }} \text { is a G.P. }\right]}\)
, \(=\frac{2^{n+1}-1}{n+1}\)]#

1 \(\frac{2^{\mathrm{n}}-1}{\mathrm{n}}\)
2 \(\frac{2^{\mathrm{n}+1}-1}{\mathrm{n}+1}\)
3 \(\frac{2^{\mathrm{n}}+1}{\mathrm{n}}\)
4 none of these
Sequence and Series

118673 If the 9th term of an AP is zero, then the ratio of 29 th term to 19 th term is

1 \(1: 2\)
2 \(1: 3\)
3 \(2: 1\)
4 \(3: 1\)
5 \(9: 1\)
Sequence and Series

118665 A arithmetic mean progression of two numbers is 6 more than the geometric mean progression of the numbers. The ratio of number is \(9: 1\), then numbers are

1 27,3
2 16,3
3 15,4
4 None of these
Sequence and Series

118666 If \(a, b\) and \(c\) are in HP, then for any \(n \in N\), which one of the following is true?

1 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}\lt 2 \mathrm{~b}^{\mathrm{n}}\)
2 \(\mathrm{a}^{\mathrm{n}}+\mathrm{c}^{\mathrm{n}}>2 \mathrm{~b}^{\mathrm{n}}\)
3 \(a^n+c^n=2 b^n\)
4 None of the above
Sequence and Series

118667 If the sum of four numbers in GP is 60 and the arithmetic mean of the first and last numbers is 18 , then the numbers are

1 \(3,9,27,81\)
2 \(4,8,16,32\)
3 2, 6, 18, 54
4 None of these