Upvote:7
1 cup of barley provides 651 calories according to the USDA, so 3000 L of barley provides about 412 days' worth of food at 2000 cal/day. An unskilled laborer making ten times this amount in a year would presumably have enough to buy a more rounded diet than just barley along with some of the basics of life. So these two seem consistent with each other.
Is it possible that "1 shekel of barley is 1 shekel of silver" means that one shekel is the same weight, whether measuring barley or silver, rather than stating the price of barley? (Certainly there are many measurement systems, even today, where the unit depends on the thing weighed -- indeed, an ounce of silver is about 31 grams, where an ounce of barley is about 28 grams.)