 
<translate> Farashin kowane 500 mL na madara daga kunshin 2 shine $ 2.50 / 2 = $ 1.25. Wannan yana nufin cewa ga kowane fakitin madara 500 mL, za ka iya ajiye $1.30 - $1.25 = $0.05. Saiti goma na fakiti 2 yana nufin 10 x 2 = fakiti 20 na 500 mL na madara. Saboda haka, jimillar kuɗin da kuka ajiye zai zama $0.05 x 20 = $1. Saboda haka, amsar ita ce 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. 