Aconvenience store sells 1/3 pound of one brand of trail mix for $1.50 and 1/2 pound of another brand of trail mix for $2.15. which brand has a lower price per pound

The cheaper trail mix would be the half pound bag. So take the price of the 1/3 bag and times it by 3 that equals $4.50 then check out the 1/2 lb bag and times it by 2 and it would equal $2.30. So you know the half pound bag is cheaper

Aand b are correctly balanced reactions. they have the same number of atoms in both sides of the reaction