If A received 30 from B, A would have twice B.

If B received 50 from A, B would have thrice A.

How much do A and B have?

solving:

A+30=2*(B-30) (i)

3*(A-50)=B+50 (ii)

Mult. (ii) by 2 and subtract (i):

5*A=490

A=98

B=1/2 * (98+30) + 30 =64+30=94

answ: (**A,B)=(98,94)**