To find Principal when Time Interest and Rate are given the rules are.



Interest = (Principal × Rate × Time)/100

Principal = (100 × Interest)/(Rate × Time)



For example:



1. Find Principal when Time = 3 years, Interest = $ 600; Rate = 4% p.a.

Solution:

Time = 3 years,

Interest = $ 600,

Rate = 4% p.a.

Principal = (100 × Interest)/(Rate × Time)

= (100 × 600)/(4 × 3)

= 60000/12

= 5000

Therefore, Principal (P) = $ 5000.



2. Find Principal when Time = 5 years, Interest = $ 500; Rate = 5% p.a.

Solution:

Time = 5 years,

Interest = $ 500,

Rate = 5% p.a.

Principal = (100 × Interest)/(Rate × Time)

= (100 × 500)/(5 × 5)

= 50000/25

= 2000

Therefore, Principal (P) = $ 2000.



3. Find Principal when Time = 4 years, Interest = $ 400; Rate = 5% p.a.

Solution:

Time = 4 years,

Interest = $ 400,

Rate = 5% p.a.

Principal = (100 × Interest)/(Rate × Time)

= (100 × 400)/(5 × 4)

= 40000/20

= 2000

Therefore, Principal (P) = $ 2000.