 
<translate> Ọnụ ego maka 500 mL mmiri ara ehi sitere na ngwugwu 2 bụ $2.50 / 2 = $1.25. Nke a pụtara na maka otu mkpọ mmiri ara ehi 500 mL, ị pụrụ ịzọpụta $1.30 - $1.25 = $0.05. Ngwakọta iri nke ngwugwu 2 pụtara 10 x 2 = ngwugwu 20 nke 500 mL mmiri ara ehi. N'ihi ya, ego niile ị na-echekwa ga-abụ $0.05 x 20 = $1. Ya mere, azịza ya bụ 1. <eng> The price per 500 mL milk from the 2 packs is $2.50 / 2 = $1.25. This means that for each pack of 500 mL milk, you can save $1.30 - $1.25 = $0.05. Ten sets of 2 packs mean 10 x 2 = 20 packs of 500 mL of milk. So, your total savings will be $0.05 x 20 = $1.
Therefore, the answer is 1. 