Repeatable-read transaction

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Table R (A) containing the records [(3), (4), (5)] and transactions T1 = UPDATE R SET A = A * 2; INSERT INTO A VALUES (6); and T2 = 'SELECT AVG (A) FROM R; SELECT AVG (A) FROM R' Knowing that transaction T2 is executed using repeatable-read which are the posible values ​​returned by the second select?

I think that possible values are: 4 and 7.5? Am I right? Please let me know if I correctly understand repeatable-read.

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