Answer: the first brand has a lower price per pound.
Explanation:
The convenience store sells 1/3 pound of one brand of trail mix for 1.50. It means that the cost of one pound of this brand of trail mix is
1/3/(1.5) = $0.22 per pound
The convenience store sells 1/2 pound of another brand of trail mix for 2.15. It means that the cost of one pound of this brand of trail mix is
1/2/(2.15) = $0.23 per pound
Therefore, the first brand($0.22 per pound) has a lower price per pound