Question 1: The height of a plant is and it is expected to grow at the rate of every month. What will be its height at the end of months?

Answer:

months

cm

Question 2: The cost of a machine is supposed to depreciate each year by of its value at the beginning of the year. If the machine is valued at at the beginning of , find its value:

- At the end of
- At the beginning of

Answer:

Years

At the end of

Rs. per cm

At the beginning of

Rs. per cm

Question 3: The value of a machine is estimated to be at the end of and at the beginning of . Supposing it depreciates at a constant rate per year of its value at the beginning of the year, calculate:

- The rate of depreciation;
- The value of the machine at the beginning of .

Answer:

Years

At the end of

At the beginning of

Question 4: The value of in article decreased for two years at the rate of per year and then in the third year it increased by . Find the original value of the article, if its value at the end of years is .

Answer:

Years

At the end of

At the end of

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

Answer:

Years

At the end of

Question 6: The population of a town decreased by during and then increased by during . Find the population of the town, at the beginning of , if at the end of its population was .

Answer:

At the end of Year

Years

At the beginning of

Years

Question 7: A sum of money, invested at compound interest, amounts to in year and to in years. Find the rate per cent and the original sum of money.

Answer:

Years

Question 8: The difference between C.I. and S.I. on for two years is at the same rate of interest per annum. Find the rate of interest.

Answer:

Simple Interest

Compound Interest

Years

Given

Question 9: A sum of money lent out at C.I. at a certain rate per annum becomes three times of itself in years. Find in how many years will the money become twenty-seven times of itself of the same rate of interest p.a.

Answer:

After 10 Years

Years

After n Years

Years

Substituting from i)

Years

Question 10: Sharma borrowed a certain sum of money at per annum compounded annually. If by paying at the end of the second year and at the end of the third he clears the debt; find the sum borrowed by him.

Answer:

Years

Third year

Years

Question 11: The difference between compound interest for a year payable half-yearly and simple interest on a certain sum of money lent out at for a year is . Find the sum of money lent out. [1998]

Answer:

Simple Interest

Compound Interest

Given

Question 12: The ages of Person 1 and Person 2 are years and years respectively. In what ratio must they invest money at p.a. compounded yearly so that both get the same sum on attaining the age of years?

Answer:

Person 1:

Years

Person 2:

Years

Given