x + y = 304,250
x = y + 51,000
Plug in (y+51,000) for x into the first equation
y+51,000+y = 304,250
Subtract 51,000 from both sides.
2y = 253,250
y = 126,625
Plug y into second equation
x = 126,625 + 51,000
x =177,625
Person A : 177,625
Person B : 126,625