Together, tim and tom have $2.40. tim has three times as much as tom. how much does each have?

X = how much Tim has
y = how much Tom has
x + y = 2.40
x = 3y
Substitute 3y for x
3y + y = 2.40
4y = 2.40
y = 0.60
Plug in y value into previous equation
x = 3(0.60)
x = 1.80
ANSWERS: Tim has $1.80 and Tom has $0.60

Hopefully this is the question you are talking about!
They want us to find the volume of model 413S in ft³
This isnt tough!
change the side measurements from Inches to Feet
12 in = 1 ft

so therefore:
24 in = 2 ft
72 in = 6 ft
18 in = 1.5 ft

Volume of a cuboid is:
Area of base × height of cuboid
V = 2 ft × 6 ft ×1.5 ft
   = 18 ft³
Volume of the cabinet (Model 413S) is 18 ft³