Question

8
(12) A sum of money becomes
of interest.
2 years at 7% per annum simple interest?
of itself in 5 years at a certain rate of simple interest. Find the rate
(13)
What sum of money lent at 12 % per annum will produce the same interest in 4 years as 8560
produces in 5 years at 12% per annum?
1
2​

Answer 1

Step-by-step explanation:

Solution 1

Let the sum be

x

and the rate be

R

%

.

x

×

(

R

+

4

)

×

2

100

−

x

×

R

×

2

100

=

60

⇒

x

×

4

×

2

100

=

60

⇒

x

=

750

Solution 2

Let the sum be

x

Simple interest on

x

at

4

%

is

60.

Therefore,

x

×

4

×

2

100

=

60

⇒

x

=

750

Solution 3

Let the sum be

x

4

%

for

2

year

⟹

60

100

%

for

1

year

⟹

60

×

25

2

=

750

Therefore, the sum is

₹

750