every wee, a grocery store buts 30 gallons of milk at a cost of $1.58 per gallon. the store owner...

every wee, a grocery store buts 30 gallons of milk at a cost of $1.58 per gallon. the store owner anticipates a 15% spoilage rate. in order to achieve a 20% markup based on selling price, what should be the selling price per gallon? i need to see the steps worked.