Question

if a field is 360 feet long and 160 feet wide, using 8 pounds of fertilizer per 1,000 square feet how many bags used to complete the job

Answer 1

First of all, you will need to find the square footage of the field
that is 360*160 
57,600
8 pounds of fertilizer covers 1,000 square feet
(I suppose each bag is 8 pounds)
to see how many square feet each bag covers 1,000/8 
each bag covers 125 square feet
to see how many bags you need, you divide the square footage of the field by how many square feet each bag covers
57,600 / 125
that is 460.8 pounds of fertilizer
460.8 / 50 is 9.216 bags of fertilizer

Hope this helps :)