1. By the information given in the problem above, you have:
 - Bottom section=x
 - The top section is one-sixth the length of the bottom section.
 Top section=x/6
 - The middle section is one-half the length of the bottom section.
 Middle section=x/2
 - The total length of the rocket is 240 ft.
 Bottom section+Top section+Middle section=240
 x+x/6+x/2=240
 2. Then, you have the the bottom section is:
 x=144
 3. Therefore, the top section is:
 Top section=x/6
 Top section=144/6
 Top section=24 ft
 The answer is: 24 ft
