Question

A sum of money at simple interest amounts to `5852 in 3
years and `7788 in 7 years. What is the rate of interest
per annum?

Answer 1

how to find principal

Answer 2

formula okay.simpleinterest=p*r*t/100

Answer 3

yes thats correct

Answer 4

principal amount

Answer 5

actually we need a different formula

Answer 6

Amount = Principal + Interest
Amount = P + P*r*t

Answer 7

thats why it wasn't working :)

Answer 8

actually i posted a wrong question sorry

Answer 9

lets simplify that formula a bit
A = P + P*r*t
A = P ( 1 + r*t)

A sum of money at simple interest amounts to `5852 in 3 years and `7788 in 7 years. What is the rate of interest per annum?

5852 = P ( 1 + r*3)
7788 = P ( 1 + r * 7 )

Answer 10

ok

Answer 11

yes

Answer 12

did you want to solve that one ?

Answer 13

it is a system of equations in two unknowns

Answer 14

yes .i am searching for that question.i forgot

Answer 15

An amount of money grows up to Rs 11520 in 2 years
and up to Rs 13824 in 3 years on compound interest.
What is the sum?

Answer 16

@perl

Answer 17

is it continuous compound interest?

Answer 18

c.I=p(1+r/100)^n

Answer 19

i dont know what you mean

Answer 20

nevermind, there is something called continuous compound interest

Answer 21

okay.

Answer 22

An amount of money grows up to Rs 11520 in 2 years and up to Rs 13824 in 3 years on compound interest. What is the sum?

Using your formula, substituting, we have

11520 = P ( 1+ r/100 ) ^2

13824 = P ( 1 + r / 100) ^3

Answer 23

notice that they both equal to P

11520/ ( 1 + r / 100) ^2 = P
13824/ ( 1 + r / 100) ^3 = P

Answer 24

yes

Answer 25

11520=13824/((100+r)/100)

Answer 26

we have to find r ah?

Answer 27

yes we can solve for r

Answer 28

1200/100+r

Answer 29

11520/ ( 1 + r / 100) ^2 = P
13824/ ( 1 + r / 100) ^3 = P

since they both equal to P
they equal to each other

11520/ ( 1 + r / 100) ^2 = 13824/ ( 1 + r / 100) ^3

so we have to solve the last equation

Answer 30

ok so far?

Answer 31

yes

Answer 32

11520=13824/((100+r)/100)

Answer 33

ok looks like you did that part correct

Answer 34

(sorry, catching up )