Answer:

Step-by-step explanation:

Principal=Rs.3000,

Time=2years

Rate=11%p.a.

Interest=  

100

P×R×T

​

T= Time period

R%= Rate of interest

P= Principal

=3000×  100 /11  ×2

⇒Rs.660

Amount=P+PI

=3000+660=Rs.3660

Step-by-step explanation:

Let the rate of interest =R%p.a.

In the first 3yrs,

principal =P=Rs7000, Time T=3yrs.

Then the interest =I

1

=

100

PRT

=

100

7000×R×3

=210R.

In the next (5-3)yrs=2yrs,

Pricipal =P=RS(7000−3000)=RS4000, Time =T=2yrs.

Then, the interest=I

2

=

100

PRT

=

100

4000×R×2

=80R.

∴ the total amount returned this time

=Rs(4000+I

1

+I

2

)=Rs5450

⟹4000+210R+80R=5450

⟹29R=1450

⟹R=5p.c.p.a.

So the rate of interest=5% p.a.