Question

the difference between simple interest and compound interest on a certain sum of money at 20% per annum for 2years is 48. find the principal

Answer 1

Let us consider the principal be x
Simple Interest = p*r*t/100
=p*20*2/100
40/100P
2/5P

Compound amount=p(1+r/100)^t
=p(1+20/100)^2
= p(120/100)^2
(6/5)^2p
(36/25)p

compound interest = amount - principal
CI=36/25P-P
CI=36/25-25/25
CI=11/25P


11/25P-2/5P=48
11/25P-10/25P=48
1/25P=48
P=48*25
P= 1200 RS

Principal will be ₹1,200

Answer 2

let the principle be x.
acc. to formula = 48 = 20*2*x/100.
= 48 = 40x/100
= 48 = 2x/5 (by assuming)
= 270 = 2x (by assuming)
= x = 270/2
= rs. 135