First set up an equation as your approach. I will use the equation x+4x=24 because that way you are saying that something pluse itself times 4 equals 24 which is what you want.
simplify the equation
5x=24
x=24/5
So you know onw piece will be 24/5 of a foot and the ither qould be that times 4 so 96/24 of a foot. In decimals it would be 4.8 and 19.2