1. Interest basics

2. Interest ∴ Interest(I)=Amount(A)-Principal(P) = 5,400-5000=Rs 400
Lokesh decides to deposit Rs in a bank for 1 year. The amount deposited is called the Principal (P). In this case, Principal (P)=Rs 5,000.
After 1 year , the bank provides him an additional amount (example Rs. 400) which is called interest. In this case, Interest (I) = Rs. 400.
The amount received after the end of 1st year is called Amount(A)
In this case, Amount (A)= Principal(P)+Interest(I) = Rs Rs. 400 = Rs 5,400.
Therefore, Principal(P)=Amount(A)-Interest(I)
∴ Interest(I)=Amount(A)-Principal(P) = 5, =Rs 400
Note: In simple interest, the interest amount remains the same because the interest is calculated based on the original principal amount. 

3. 5000 500 ? We know that A=P+I A=5000+500 ∴ A=5500 12,500 ? 17,500
Fill in the blanks
Principal Interest Amount
(P) (I) (A) ?
We know that A=P+I A=
∴ A=5500
12, ? ,500
We know that I=A-P I=
∴ I=5000 ?
We know that P=A-I P=
∴ P=19000

4. Try these Find amount when principal is Rs 2500 and interest is Rs 275
Find Interest when principal is Rs 1600 and amount is Rs 2150
Find principal when interest is Rs 420 and amount is Rs 900