Given:-
Simple intrest is $1240. Rate is 4.00%. Time is 2 years.
To find:-
The principal amount.
The formula which relates Simple intrest, Rate, Time and Principal amount is,

So from this the formula for p is,

Subsituting the known values. we get,

By simplifying the above equation. we get the value of p,

So the principle amount value is 15500.