A vendor receives a commission of 2.50 Ghana cedis on each pack (12 bottles ) of mineral water sold.In a week , the vendor sold 612 bottles of mineral water. find the commission earned that week

The number of packs sold can be found by dividing the total number of bottles sold by the number of bottles in each pack: 612 bottles / 12 bottles/pack = <<612/12=51>>51 packs

The commission earned that week is found by multiplying the commission per pack by the number of packs sold: 2.50 GHS/pack * 51 packs = <<2.5*51=127.5>>127.5 GHS. Answer: \boxed{127.5}.