Total investment = 12,000
Let x be invested in Stock at a return of 14%
The rest (12,000-x) invested at a loss of 6%
0.14*x - 0.06*(12,000-x) = 680
0.14x -720 +0.06x = 680
0.2x = 1400
x = 7000
So $7,000 was invested at a rate of 6% and $5,000 (12000-7000) was invested at a loss of 6%