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# Selina solutions for Class 9 chapter 3 - Compound Interest (Using Formula)

#### Chapters

Chapter 1: Rational and Irrational Numbers

Chapter 2: Compound Interest (Without using formula)

Chapter 3: Compound Interest (Using Formula)

Chapter 4: Expansions (Including Substitution)

Chapter 5: Factorisation

Chapter 6: Simultaneous (Linear) Equations (Including Problems)

Chapter 7: Indices (Exponents)

Chapter 8: Logarithms

Chapter 9: Triangles [Congruency in Triangles]

Chapter 10: Isosceles Triangles

Chapter 11: Inequalities

Chapter 12: Mid-point and Its Converse [ Including Intercept Theorem]

Chapter 13: Pythagoras Theorem [Proof and Simple Applications with Converse]

Chapter 14: Rectilinear Figures [Quadrilaterals: Parallelogram, Rectangle, Rhombus, Square and Trapezium]

Chapter 15: Construction of Polygons (Using ruler and compass only)

Chapter 16: Area Theorems [Proof and Use]

Chapter 17: Circle

Chapter 18: Statistics

Chapter 19: Mean and Median (For Ungrouped Data Only)

Chapter 20: Area and Perimeter of Plane Figures

Chapter 21: Solids [Surface Area and Volume of 3-D Solids]

Chapter 22: Trigonometrical Ratios [Sine, Consine, Tangent of an Angle and their Reciprocals]

Chapter 23: Trigonometrical Ratios of Standard Angles [Including Evaluation of an Expression Involving Trigonometric Ratios]

Chapter 24: Solution of Right Triangles [Simple 2-D Problems Involving One Right-angled Triangle]

Chapter 25: Complementary Angles

Chapter 26: Co-ordinate Geometry

Chapter 27: Graphical Solution (Solution of Simultaneous Linear Equations, Graphically)

Chapter 28: Distance Formula

## Chapter 3: Compound Interest (Using Formula)

Exercise 3(A)Exercise 3(B)Exercise 3(C)Exercise 3(D)Exercise 3(E)

#### Selina solutions for Class 9 Chapter 3 Exercise Exercise 3(A) [Page 44]

Exercise 3(A) | Q 1 | Page 44

Find the amount and the compound interest on Rs. 12,000 in 3 years at 5% compounded annually.

Exercise 3(A) | Q 2 | Page 44

Calculate the amount of Rs. 15,000 is lent at compound interest for 2 years and the rates for the successive years are 8% and 10% respectively.

Exercise 3(A) | Q 3 | Page 44

Calculate the compound interest accrued on Rs. 6,000 in 3 years, compounded yearly, if the rates for the successive years are 5%, 8% and 10% respectively.

Exercise 3(A) | Q 4 | Page 44

What sum of money will amount to Rs. 5,445 in 2 years at 10% per annum compound interest ?

Exercise 3(A) | Q 5 | Page 44

On what sum of money will the compound interest for 2 years at 5% per annum amount to Rs. 768.75?

Exercise 3(A) | Q 6 | Page 44

Find the sum on which the compound interest for 3 years at 10% per annum amounts to Rs. 1,655.

Exercise 3(A) | Q 7 | Page 44

What principal will amount to Rs. 9,856 in two years, if the rates of interest for successive years are 10% and 12% respectively ?

Exercise 3(A) | Q 8 | Page 44

On a certain sum, the compound interest in 2 years amounts to Rs. 4,240. If the rate of interest for the successive years is 10% and 15% respectively, find the sum.

Exercise 3(A) | Q 9 | Page 44

At what per cent per annum will Rs.6,000 amount to Rs.6,615 in 2 years when interest is compounded annually?

Exercise 3(A) | Q 10 | Page 44

At what rate per cent compound interest, does a sum of money become 1.44 times of itself in 2 years ?

Exercise 3(A) | Q 11 | Page 44

At what rate per cent will a sum of Rs. 4,000 yield Rs.1,324 as compound interest in 3 years ?

Exercise 3(A) | Q 12 | Page 44

A person invests Rs5,000 for three years at a certain rate of interest compounded annually. At the end of two years this sum amounts to Rs6,272. Calculate :
(i) the rate of interest per annum.
(ii) the amount at the end of the third year.

Exercise 3(A) | Q 13 | Page 44

In how many years will Rs. 7,000 amount to Rs. 9,317 at 10% per annum compound interest ?

Exercise 3(A) | Q 14 | Page 44

Find the time, in years, in which Rs. 4,000 will produce Rs. 630.50 as compound interest at 5% compounded annually.

Exercise 3(A) | Q 15 | Page 44

Divide Rs. 28,730 between A and B so that when their shares are lent out at 10% compound interest compounded per year, the amount that A receives in 3 years is the same as what B receives in 5 years.

Exercise 3(A) | Q 16 | Page 44

A sum of Rs 44,200 is divided between John and Smith, 12 years and 14 years old respectively, in such a way that if their portions be invested at 10% per annum compound interest, they will receive equal amounts on reaching 16 years of age.
(i) What is the share of each out of Rs44,200 ?
(ii) What will each receive, when 16years old ?

Exercise 3(A) | Q 17 | Page 44

The simple interest on a certain sum of money and at 10% per annum is Rs. 6,000 in 2 years, Find:

1. the sum.
2. the amount due to the end of 3 years and at the same rate of interest compounded annually.
3. the compound interest earned in 3 years.
Exercise 3(A) | Q 18 | Page 44

Find the difference between compound interest and simple interest on Rs. 8,000 in 2 years and at 5% per annum.

#### Selina solutions for Class 9 Chapter 3 Exercise Exercise 3(B) [Page 46]

Exercise 3(B) | Q 1 | Page 46

The difference between simple interest and compound interest on a certain sum is Rs. 54.40 for 2 years at 8 per cent per annum. Find the sum.

Exercise 3(B) | Q 2 | Page 46

A sum of money, invested at compound interest, amounts to Rs. 19,360 in 2 years and to Rs. 23,425.60 in 4 years. Find the rate per cent and the original sum of money.

Exercise 3(B) | Q 3 | Page 46

A sum of money lent out at C.I. at a certain rate per annum becomes three times of itself in 8 years. Find in how many years will the money becomes twenty-seven times of itself at the same rate of interest p.a.

Exercise 3(B) | Q 4 | Page 46

On what sum of money will compound interest (payable annually) for 2 years be the same as simple interest on Rs. 9,430 for 10 years, both at the rate of 5 per cent per annum ?

Exercise 3(B) | Q 5 | Page 46

Kamal and Anand each lent the same sum of money for 2 years at 5% at simple interest and compound interst respectively. Anand recived Rs. 15 more than Kamal. Find the amount of money lent by each and the interest received.

Exercise 3(B) | Q 6 | Page 46

Simple interest on a sum of money for 2 years at 4% is Rs. 450. Find compound interest of the same sum and at the same rate for 2 years.

Exercise 3(B) | Q 7 | Page 46

Simple interest on a certain sum of money for 4 years at 4% per annum exceeds the compound interest on the same sum for 3 years at 5 per cent per annum by Rs. 228. Find the sum.

Exercise 3(B) | Q 8 | Page 46

Compound interest on a certain sum of money at 5% per annum for two years is Rs. 246. Calculate simple interest on the same sum for 3 years at 6% per annum.

Exercise 3(B) | Q 9 | Page 46

A certain sum of money amounts to Rs. 23,400 in 3 years at 10% per annum simple interest. Find the amount of the same sum in 2 years and at 10% p.a. compound interest.

Exercise 3(B) | Q 10 | Page 46

Mohit borrowed a certain sum at 5% per annum compound interest and cleared this loan by paying Rs. 12,600 at the end of the first year and Rs. 17,640 at the end of the second year. Find the sum borrowed.

#### Selina solutions for Class 9 Chapter 3 Exercise Exercise 3(C) [Page 50]

Exercise 3(C) | Q 1 | Page 50

If the interest is compounded half-yearly, calculate the amount when principal is Rs. 7,400; the rate of interest is 5% per annum and the duration is one year.

Exercise 3(C) | Q 2 | Page 50

Find the difference between the compound interest compounded yearly and half-yearly on Rs. 10,000 for 18 months at 10% per annum.

Exercise 3(C) | Q 3 | Page 50

A man borrowed Rs.16,000 for 3 years under the following terms:
20% simple interest for the first 2 years.
20% C.I. for the remaining one year on the amount due after 2 years, the interest being compounded half-yearly.
Find the total amount to be paid at the end of the three years.

Exercise 3(C) | Q 4 | Page 50

What sum of money will amount to Rs. 27,783 in one and a half years at 10% per annum compounded half yearly ?

Exercise 3(C) | Q 5 | Page 50

Ashok invests a certain sum of money at 20% per annum, compounded yearly. Geeta invests an equal amount of money at the same rate of interest per annum compounded half-yearly. If Geeta gets Rs. 33 more than Ashok in 18 months, calculate the money invested.

Exercise 3(C) | Q 6 | Page 50

At what rate of interest per annum will a sum of Rs. 62,500 earn a compound interest of Rs. 5,100 in one year? The interest is to be compounded half yearly.

Exercise 3(C) | Q 7 | Page 50

In what time will Rs. 1,500 yield Rs. 496.50 as compound interest at 20% per year compounded half-yearly ?

Exercise 3(C) | Q 8 | Page 50

Calculate the C.I. on Rs. 3,500 at 6% per annum for 3 years, the interest being compounded half-yearly.
Do not use mathematical tables. Use the necessary information from the following:
(1.06)3 =1.191016; (1.03)3 = 1.092727
(1.06)6 =1.418519; (1.03)6 = 1.194052

Exercise 3(C) | Q 9 | Page 50

Find the difference between compound interest and simple interest on Rs.12,000 and in  1 1/2 years at 10% compounded yearly.

Exercise 3(C) | Q 10 | Page 50

Find the difference between compound interest and simple interest on Rs. 12,000 and in 1 1/2 years at 10% compounded half-yearly.

#### Selina solutions for Class 9 Chapter 3 Exercise Exercise 3(D) [Pages 53 - 54]

Exercise 3(D) | Q 1 | Page 53

The cost of a machine is supposed to depreciate each year at 12% of its value at the beginning of the year. If the machine is valued at Rs. 44,000 at the beginning of 2008, find its value :
(i) at the end of 2009.
(ii) at the beginning of 2007.

Exercise 3(D) | Q 2 | Page 53

The value of an article decreases for two years at the rate of 10% per year and then in the third year it increases by 10%. Find the original value of the article, if its value at the end of 3 years is Rs. 40,095.

Exercise 3(D) | Q 3 | Page 53

According to a census taken towards the end of the year 2009, the population of a rural town was found to be 64,000. The census authority also found that the population of this particular town had a growth of 5% per annum. In how many years after 2009 did the population of this town reach 74,088 ?

Exercise 3(D) | Q 4 | Page 53

The population of a town decreased by 12% during 1998 and then increased by 8% during 1999. Find the population of the town, at the beginning of 1998, if at the end of 1999 its population was 2,85,120.

Exercise 3(D) | Q 5 | Page 53

A sum of money, invested at compound interest, amounts to Rs. 16,500 in 1 year and to Rs. 19,965 in 3 years. Find the rate per cent and the original sum of money invested.

Exercise 3(D) | Q 6 | Page 53

The difference between C.I. and S.I. on Rs. 7,500 for two years is Rs. 12 at the same rate of interest per annum. Find the rate of interest.

Exercise 3(D) | Q 7 | Page 53

A sum of money lent out at C.I. at a certain rate per annum becomes three times of itself in 10 years. Find in how many years will the money become twenty-seven times of itself at the same rate of interest p.a.

Exercise 3(D) | Q 8 | Page 54

Mr. Sharma borrowed a certain sum of money at 10% per annum compounded annually. If by paying Rs.19,360 at the end of the second year and Rs. 31,944 at the end of the third year he clears the debt; find the sum borrowed by him.

Exercise 3(D) | Q 9 | Page 54

The difference between compound interest for a year payable half-yearly and simple interest on a certain sum of money lent out at 10% for a year is Rs. 15. Find the sum of money lent out.

Exercise 3(D) | Q 10 | Page 54

The ages of Pramod and Rohit are 16 years and 18 years respectively. In what ratio must they invest money at 5% p.a. compounded yearly so that both get the same sum on attaining the age of 25 years?

#### Selina solutions for Class 9 Chapter 3 Exercise Exercise 3(E) [Page 54]

Exercise 3(E) | Q 1 | Page 54

Simple interest on a sum of money for 2 years at 4% is Rs .450. Find compound interest on the same sum and at the same rate for 1 year, if the interest is reckoned half yearly.

Exercise 3(E) | Q 2 | Page 54

Find the compound interest to the nearest rupee on Rs. 10,800 for 2 1/2 years at 10% per annum.

Exercise 3(E) | Q 3 | Page 54

The value of a machine, purchased two years ago, depreciates at the annual rate of 10%. If its present value is Rs.97,200, find:

1.   Its value after 2 years.
2.   Its value when it was purchased.
Exercise 3(E) | Q 4 | Page 54

Anuj and Rajesh each lent the same sum of money for 2 years at 8% simple interest and compound interest respectively. Rajesh received Rs. 64 more than Anuj. Find the money lent by each and interest received.

Exercise 3(E) | Q 5 | Page 54

Calculate the sum of money on which the compound interest (payable annually) for 2 years be four times the simple interest on Rs. 4,715 for 5 years, both at the rate of 5% per annum.

Exercise 3(E) | Q 6 | Page 54

A sum of money was invested for 3 years, interest being compounded annually. The rates for successive years were 10%, 15% and 18% respectively. If the compound interest for the second year amounted to Rs. 4,950, find the sum invested.

Exercise 3(E) | Q 7 | Page 54

A sum of money is invested at 10% per annum compounded half yearly. If the difference of amounts at the end of 6 months and 12 months is Rs.189, find the sum of money invested.

Exercise 3(E) | Q 8 | Page 54

Rohit borrows Rs. 86,000 from Arun for two years at 5% per annum simple interest. He immediately lends out this money to Akshay at 5% compound interest compounded annually for the same period. Calculate Rohit's profit in the transaction at the end of two years.

Exercise 3(E) | Q 9 | Page 54

The simple interest on a certain sum of money for 3 years at 5% per annum is Rs.1,200. Find the amount and the compound interest due on this sum of money at the same rate and after 2 years. Interest is reckoned annually.

Exercise 3(E) | Q 10 | Page 54

Nikita invests Rs.6,000 for two years at a certain rate of interest compounded annually. At the end of first year it amounts to Rs.6,720. Calculate:
(a) The rate of interest.
(b) The amount at the end of the second year.

## Chapter 3: Compound Interest (Using Formula)

Exercise 3(A)Exercise 3(B)Exercise 3(C)Exercise 3(D)Exercise 3(E)

## Selina solutions for Class 9 Mathmetics chapter 3 - Compound Interest (Using Formula)

Selina solutions for Class 9 chapter 3 (Compound Interest (Using Formula)) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Selina Concise Class 9 Mathematics solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Class 9 Mathmetics chapter 3 Compound Interest (Using Formula) are Conept of Compound Interest, Inverse Formula, Miscellaneous Problem, When the Interest is Compounded Half Yearly, When the Time is Not an Exact Number of Years and the Interest is Compounded Yearly, Use of Compound Interest in Computing Amount Over a Period of 2 Or 3-years.

Using Selina Class 9 solutions Compound Interest (Using Formula) exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 9 prefer Selina Textbook Solutions to score more in exam.

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