Question

Babu deposited a certain Amount in a bank which gives 10% simple interest anually. After two years, he got 400 rupees interest, if he deposited the same amount in another bank giving 10% compounded interest anually. How much interest he would have got?

Answer 1

principal=p
r=10%
time=2y
SI=400rps
SI=p*r*t*/100
400=p*10*2/100
400=1/5p
p=400*5
p=2000



therefore, principal=2000rps
CA=p(1+r/100)^t
=2000(1+10/100)^2
=2000(110/100)^2
=2000*110/100*110/100
=2420
CI= CA-P
=24200-2000
=242rps (and)

Answer 2

Answer:

Equation for finding simple interest :-

P×r/100×n

P means the starting amount

r means the rate of interest

n means the number of year

to find answer for this question=

P×10/100×2=400

=400/2=200

=200× 100/10

=2000

i.e he deposited 2000 rupees

Then he deposited the same amount in an another bank giving 10% compounded annually

so the equation=

P(1+r/100)^n

so 2000(1+10/100)^2

=2000×110/100×110/100

=2420 rupees

To find the answer 2420-2400= 20 rupees