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?

Feb 28, 2015

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)

Feb 28, 2015

You get:
$88 f t \cdot 9 \frac{n a i l s}{f t} = 792 n a i l s$
$\frac{792 n a i l s}{36 \frac{n a i l s}{p o u n d}} = 22 p o u n \mathrm{ds}$
22pounds*69cents=1518cents=15.18\$

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