Answer:
 $50,000 in stocks
 $40,000 in bonds
 $25,000 in CDs
Step-by-step explanation:
Let c represent the amount invested in CDs. Then the amount invested in bonds is (c+15000) and the amount invested in stocks is (115000 -c -(c+15000)) = (100000 -2c). The total interest earned is ...
 0.04c +0.053(c +15000) +0.062(100,000 -2c) = 6220
 -0.031c +795 +6200 = 6220
 -0.031c = -775 . . . . . . . . . . . . . . . subtract the left-side constants
 c = 25000 . . . . . . . . . . divide by the coefficient of c
 c+15000 = 40000 . . . . bonds
 100000 -2c = 50000 . . . . . stocks
Maricopa Success invested ...
 $50,000 in stocks
 $40,000 in bonds
 $25,000 in CDs