T1=120, T2=10, T3=10. A owns ½ of T1, all of T2 and ½ of T3. A sells B 10. allocate

Question

A owns 60 acres in a 120 acre tract (1), 10 acres in a 10 acre tract (2) and 5 acres in a 10 acre tract (3).  A sells B 10 acres.  How many acres does B own in Tract 1?