Genesis 37:28
26 Then Judah said to his brothers, “What profit is there if we kill our brother and cover up his blood? 27 Come, let’s sell him to the Ishmaelites, but let’s not lay a hand on him, for after all, he is our brother, our own flesh.” His brothers agreed. 28 So when the Midianite merchants passed by, Joseph’s brothers pulled him out of the cistern and sold him to the Ishmaelites for 20 pieces of silver. The Ishmaelites then took Joseph to Egypt. 29 Later Reuben returned to the cistern to find that Joseph was not in it! He tore his clothes, 30 returned to his brothers, and said, “The boy isn’t there! And I, where can I go?”
LXX Genesis 37:28
26 Then Ioudas said to his brothers, “What advantage is it if we kill our brother and conceal his blood? 27 Come, let us sell him to these Ismaelites, but let our hands not be upon him, because he is our brother and our flesh.” And his brothers listened. 28 And some Madienite traders were passing by, and they drew out and brought up Ioseph from the pit and sold Ioseph to the Ismaelites for twenty gold pieces, and they brought Ioseph down to Egypt. 29 Then Rouben returned to the pit, and he did not see Ioseph in the pit, and he tore his clothes. 30 And he returned to his brothers and said, “The youngster is not thereb, and I, where shall I yet go?”
Notes and References
"... Genesis 37:28 contains another example of culturally based adaptation. The point at issue here is the price for which Joseph is sold by his brothers to the Ishmaelites ... As it turns out, the average price for a slave in the time and place of the LXX translator was considerably higher than the twenty silver pieces mentioned in the Hebrew text. The intended denomination is undoubtedly the shekel, which was equivalent to the Greek didrachma. Papyrus evidence from 3 B.C. indicates that the χρύσεος / χρυσοῦς ('gold') was equivalent to twenty silver drachmas or ten didrachmas. Thus, the Greek translator set a price that would have been more in line with the going rate in 3 B.C. Alexandrian slave markets ..."
Hiebert, Robert J. V. Translation Technique in the Septuagint of Genesis and its Implications for the NETS Version (pp. 76-93) International Organization for Septuagint and Cognate Studies, Vol. 33, 2000