A+b=42, that is to say, A plus B equals 42 (for example, 3 books plus 2 books equals 5 books, so taking 2 books out of 5 books leaves 3 books), then taking A from 42 books leaves B, that is, B = 42-A.

C=32-a in the same way, a+c=32.

Because b+c=44

Then (42-a)+(32-a)=44, and a= 15.

So a+c=32 c= 17.

a+b=42 b=27