Then: A+B=28, B+C=25, A+C=23.

A+B+A+C=28+23

2A+B+C=5 1

2A+25=5 1

A=(5 1-25)/2= 13

13+C=23

C= 10

B+ 10=25

B= 15

Solution: A= 13, B= 15, C= 10.