Start with x+y =30,000
so x=30,000-y we will come back to this
.06x+.12y= 2,460
.06(30,000-y)+.12y =2,460
multiply
1800 - .06y+.12y =2,460
combine ys
1800 +.06y = 2,460
.06y = 660 (subtracting 1800 from both sides)
y=11,000
Back to the orginal
x+11000 = 30,000
x=19,000