Question

This is simple interest : $640, 3%, 2 years anyone knows how to explain?

Answer 1

I=PRT
Interest=I
P=principal
R=rate in decimal
T=time in years

given
asuming 640 is the principal and not the interest
P=640
R=3%=0.03
T=2


I=640*0.03*2
I=19.2*2
I=38.4

interst=$38.40