Final answer:
To find the wall space needed for a 30-shelf cupboard, calculate the space per shelf (1.5 ft) by dividing 18 ft by 12 shelves and then multiply by 30 shelves, resulting in 45 ft.
Step-by-step explanation:
The question asks for the amount of wall space needed for a cupboard with a different number of shelves using a ratio based on the space a smaller cupboard uses. We need to find the wall space for a 30-shelf cupboard given that a 12-shelf cupboard requires 18 ft of wall space.
We first calculate the wall space per shelf by dividing the total wall space by the number of shelves in the original cupboard. So, 18 ft of wall space for 12 shelves means each shelf requires 1.5 ft of wall space (18 ft ÷ 12 = 1.5 ft).
Next, we multiply the wall space per shelf by the number of shelves in the new cupboard: 1.5 ft per shelf × 30 shelves equals to 45 ft of wall space required for the 30-shelf cupboard.