check the picture below.
so it has a base of 18x18 and a height of that much.

Answer:
The initial distance between Wade and Alexandra is 240ft.
They walk towards each other.
Alexandra walks twice as fast as Wade.
Now, because they are walking towards each other, when the distance walked by both of them equals 240 ft, they will meet.
Then:
if Wade walks z ft, Alexandra walks 2*z ft.
So we have the equation:
Distance that Wade walked + Distance that Alexandra walked = 240ft
z + 2*z = 240ft
3*z = 240ft
z = 240ft/3 = 80ft
They will meet when Wade walks 80ft.
The answer is c, because you have the multiply the sides