constant or variable?

Question

if I = P*R*T what are I, P, R, and T? constants or variables?

Answer 1

Variables, because the rate, time, etc. is different for different situations (for example one bank might charge fees more or less then another bank.)

Answer 2

Variables.

Answer 3

Each symbol is a variable until you assign a specific value to the symbol at which time that symbol becomes a constant.

Answer 4

they are constants but you must be given values to plug in