## Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Additional Questions

These Solutions are part of Selina Concise Mathematics Class 10 ICSE Solutions. Here we have given Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Additional Questions

**Other Exercises**

- Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Ex 11A
- Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Ex 11B
- Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Ex 11C
- Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Ex 11D
- Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Additional Questions

**Question 1.**

**Find the sum of n terms of the series :**

**(i) 4 + 44 + 444 + ….**

**(ii) 0.8 + 0.88 + 0.888 + ….**

**Solution:**

(i) 4 + 44 + 444 + ….

= \(=\frac { 4 }{ 9 } \left[ 9+99+999+…. \right] \)

**Question 2.**

**Find the sum of infinite terms of each of the following geometric progression:**

**(i)\(1+\frac { 1 }{ 3 } +\frac { 1 }{ 9 } +\frac { 1 }{ 27 } +…\)**

**(ii)\(1-\frac { 1 }{ 2 } +\frac { 1 }{ 4 } -\frac { 1 }{ 8 } +…\)**

**(iii)\(\frac { 1 }{ 3 } +\frac { 1 }{ { 3 }^{ 2 } } -\frac { 1 }{ { 3 }^{ 3 } } +…\)**

**(iv)\(\sqrt { 2 } -\frac { 1 }{ \sqrt { 2 } } +\frac { 1 }{ 2\sqrt { 2 } } -\frac { 1 }{ 4\sqrt { 2 } } +…\)**

**(v)\(\sqrt { 3 } +\frac { 1 }{ \sqrt { 3 } } +\frac { 1 }{ 3\sqrt { 3 } } +\frac { 1 }{ 9\sqrt { 3 } } +… \)**

**Solution:**

(i)\(1+\frac { 1 }{ 3 } +\frac { 1 }{ 9 } +\frac { 1 }{ 27 } +…\) upto infinity

S_{n} = \(\\ \frac { a }{ 1-r } \)

**Question 3.**

**The second term of a G.P. is 9 and sum of its infinite terms is 48. Find its first three terms.**

**Solution:**

In a G.P.

T_{2} = 9, sum of infinite terms = 48

Let a be the first term and r be the common ratio, therefore,

S_{∞} = \(\\ \frac { a }{ 1-r } \)

**Question 4.**

**Find three geometric means between \(\\ \frac { 1 }{ 3 } \) and 432.**

**Solution:**

Let G_{1}, G_{2} and G_{3} be three means between

\(\\ \frac { 1 }{ 3 } \) and 432, then

**Question 5.**

**Find :**

**(i) two geometric means between 2 and 16**

**(ii) four geometric means between 3 and 96.**

**(iii) five geometric means between \(3 \frac { 5 }{ 9 } \) and \(40 \frac { 1 }{ 2 } \).**

**Solution:**

(i) Two G.M. between 2 and 16

Let G_{1} , and G_{1} be the G.M.,

then 2, G_{1}, G_{2}, 16

**Question 6.**

**The sum of three numbers in G.P. is \(\\ \frac { 39 }{ 10 } \) and their product is 1. Find numbers**

**Solution:**

Sum of three numbers in G.P = \(\\ \frac { 39 }{ 10 } \)

and their product = 1

**Question 7.**

**Find the numbers in G.P. whose sum is 52 and the sum of whose product in pairs is 624.**

**Solution:**

Sum of 3 numbers in G.P. = 52

and their product in pairs = 624

Let numbers be a, ar, ar²

**Question 8.**

**The sum of three numbers in G.P. is 21 and the sum of their squares is 189. Find the numbers.**

**Solution:**

Sum of three numbers in G.P. = 21

Sum of their squares = 189

Let three numbers be a, ar, ar², then

a + ar + ar² = 21

=> a( 1 + r + r²) = 21….(i)

Hope given Selina Concise Mathematics Class 10 ICSE Solutions Chapter 11 Geometric Progression Additional Questions are helpful to complete your math homework.

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