Elsie’s ain’t borrows $400 with an interest rate of 1.5% how much interest will she pay after 4 years?

Formula I = P x r x t
p is the principal amount, $400.00
r is the interest rate 1.5% a yea (0.015 in decimal)
t is time involved 4 years
so t is 4 year time periods

To find the simple interest we multiply 400 x 0.015 x 4 to get $24.00

so if you borrowed the $400 dollars you would now owe $424

so it's $24 interest or $424 since it's usually added to the principal