[tex] \frac{50 \: lbs}{29.98} = \frac{1 \: lb}{0.596} [/tex]
[tex] \frac{ 25 \: lbs}{15.49} = \frac{1 \: lb}{0.6196} [/tex]
[tex] \frac{1 \: lb}{0.596} < \frac{1 \: lb}{0.6196} [/tex]
Since the proportions are different, it's best to say that to determine the price of a 40-pound bag, proportional reasoning is no where to be found so no, proportional reasoning cannot be used to find the price of a 40-pound bag!
