#### Explanation:

As one pound is equal to $16$ ounces, we can write $5$ pounds and $12$ ounces as $5 \frac{12}{16} = 5 \frac{3}{4} = \frac{23}{4}$ pounds.

Now $\frac{23}{4}$ pounds of potatoes cos $2.07=207/100 Hence, one pond of potatoes cost $\frac{\frac{207}{100}}{\frac{23}{4}}$= $\frac{207}{100} \times \frac{4}{23}$= $\frac{9 \cancel{207}}{100} \times \frac{4}{1 \cancel{23}}$= $\frac{36}{100} = 0.36$Hence, one pound of potatoes cost $0.36 or $36$ cents.

Jun 9, 2016

Another approach. Really it is the same thing in disguise!

$0.36 #### Explanation: To start with this be the same as the other solution. Will very slightly change in the middle. Then end up the same again. The important thing to remember is that $16 o z = 1 l b$'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Given weight $\text{ "5color(white)(.) lb" " +" } \frac{12}{16} \textcolor{w h i t e}{.} l b$This is the same as $5 \frac{3}{4} \textcolor{w h i t e}{.} l b \to 5.75 \textcolor{w h i t e}{.} l b$The cost is $2.07 so as a ratio we have:

($2.07)/(5.75color(white)(.)lb) But we need the cost for $1 \textcolor{w h i t e}{.} l b$Let the unknown cost be $x$, then by the law of ratios we have ($2.07)/(5.75color(white)(.)lb) -= x/(1color(white)(.)lb)

But $\frac{x}{1}$ is the same as just having $x$ so

x=($2.07)/(5.75color(white)(.)lb)" "=" "$0.36