Linear Systems question

Question

Maricopa's Success scholarship fund receives a gift of $ 145000. The money is invested in stocks, bonds, and CDs. CDs pay 4.25 % interest, bonds pay 3.3 % interest, and stocks pay 11.3 % interest. Maricopa Success invests $ 20000 more in bonds than in CDs. If the annual income from the investments is $ 7260 , how much was invested in each account?

 

Maricopa Success invested $__________in stocks.
Maricopa Success invested $ __________in bonds.
Maricopa Success invested $ ___________in CDs.

Answer 1

let

Maricopa invested in stocks = x

Maricopa invested in cds = y

Maricopa invested in bonds= y+20000

 

 

 

interest from stock = x*11.3% = x* 0.113 = 0.113x

interest from cds = y*4.25%= y*0.425 =0.425y

interest from bond =(y+20000)*3.3%= (y+20000)*0.033=0.033y+660

 

so now we can write 2 equations

 

Maricopa's Success scholarship fund receives a gift of $ 145000.

x +y +y+20000 =145000

x+2y =125000  ..............eq 1

 

 

the annual income from the investments is $ 7260

0.113x+0.425y+0.033y+600=7260

0.113x+0.458y = 6660.............eq 2

 

solve these 2 equation to get the answers