6 packs of tuna fish are sold per hour. If the sales are made for 15 hours, the total number of packs sold is 4=6*15 = <<6*15=90>>90 packs.
At $60 per pack, during a high season, the total sales in 15 hours are 90*$60 = $<<90*60=5400>>5400
4 packs of tuna fish are sold per hour. If the sales are made for 15 hours, the total number of packs sold is 4*15 = <<4*15=60>>60 packs.
At $60 per pack, during a low season, the total sales in 15 hours are 60*$60 = $<<60*60=3600>>3600
The amount of money that is made after 15 hours during a high season than a low season is $5400-$3600 = $<<5400-3600=1800>>1800
#### 1800