Question 30300
A+B=111
A-B=63
THEREFORE A=B+63 SUBSTITUTING A=B+63 IN THE FIRST EQUATION WE GET 
B+63+B=111 OR 2B+63=111 OR 2B=111-63 OR 2B=48 THEREFORE B=24 & A+24=111 OR 
A=111-24 OR A=87 AND 87-24=63.