Question

Janice is building shelving for her office . Each shelf will be 3 feet 9" in length . She can buy boards that are 13 & a half feet long. How many boards does seh need to buy to make 30 shelves

Answer 1

She need to buy 8 boards.

Explanation:

Given:

Number of shelves = 30

Length of each shelf = 3 ft 9 inches

Length of each board she can buy =
`13(1)/(2)\ ft`

Now, using Unitary method, finding the total length of the 30 shelves.

Length of 1 shelf = 3 ft 9 in =
`3 + (9)/(12)=3+0.75=3.75\ ft`

∴ Length of 30 shelves =
`30* 3.75=112.5\ ft`

Now, the number of boards that she can buy is given by dividing the total length of the shelves and length of each board. Thus,

Number of boards =
`\frac{\textrm{Total length of shelves}}{\textrm{Length of each board}}`

Number of boards =
`(112.5)/(13.5)=8.33\approx8`

Therefore, the number of boards she can buy are 8.