One brand of cookies is sold in three different box sizes: small, medium, and large. The small box has half the volume of the medium box. The large box has twice the volume of the medium box. The volume of the medium box is x.
If someone buys one of each size, which expression shows the combined volume of the three boxes?
A
1.75x
B
2.5x
C
3.5x
D
7x
