Question

What would be the cost in dollars of nails for a fence 88 feet long if one needs 9 nails per foot of fence, there are 36 nails in a pound, and they sell for 69 cents per pound?

Answer 1

Arrange the ratios so that when multiplied together the units of measurement cancel out (except for the required units of the answer.

`(88 ft )/(fence)xx(9 nails)/(ft)xx(1 pound)/(36 nails)xx($ 0.69)/(1 pound)`

`= ($14.96)/(fence)`

Answer 2

You get:
`88 ft *9 (nails)/(ft)=792 nails`
`(792nails)/(36(nails)/(pound))=22 pounds`
`22pounds*69cents=1518cents=15.18$`

(hope I am right with US units of currency!!!)