Question 173441
Let the cost of one lb. of sweet potatoes = s
Let the cost of one lb. of apples = a
Let the cost of one lb. of onions = n (I chose n to represent onions so that there is no possibility that o ("oh") can be confused with 0 ("zero").


Givens:
1. {{{9s=6a}}}
2. {{{s=2n}}}
3. {{{a=n+24}}}


Use substitution:

{{{cartoon(9*red(s)=6*green(a),9*red(2n)=6*(green(n+24)))}}}


{{{18n=6n+144}}}


{{{12n=144}}}


{{{n=12}}}


Since the only given constant value was expressed in cents, the value of {{{n}}} must also be in cents.  Hence, onions cost 12 cents per pound.


Apples, then, must cost {{{12+24=36}}} cents per pound and sweet potatoes cost {{{2(12)=24}}} cents per pound.


Either this is a VERY old problem, or I want to know where to find this grocery store!