SOLUTION: QUESTION 1: Cyndee wants to invest $50,000. Her financial planner advises her to invest in three types of accounts: one paying 3%, one paying 4.5%, and one paying 5% simple intere

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: QUESTION 1: Cyndee wants to invest $50,000. Her financial planner advises her to invest in three types of accounts: one paying 3%, one paying 4.5%, and one paying 5% simple intere      Log On


   



Question 1040424: QUESTION 1:
Cyndee wants to invest $50,000. Her financial planner advises her to invest in three types of accounts: one paying 3%, one paying 4.5%, and one paying 5% simple interest per year. Cyndee wants to put twice as much in the lowest-yielding, least-risky account as in the highest-yielding account. How much should she invest in each account to achieve a total annual return of $1900?
x for the 3% act, y for the 4.5% act and z for the 5% act
I tried the equations:
.03x+.045(50,000-x-2x)+.05(2x)=1900
and .05x+.045(50,000-x-2x)+.03x=1900.
The system I came up with was:
x+y+z=1900
.03x+.045y+.05z=1900
x=2z


Please help! Thank you!

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
x=3%; (1/2)x=5%, 50000-(3/2)x=4.5%. Twice as much is in the lower as the upper, not the reverse
.03x+0.045(50000-(3/2)x)+0.05(1/2)x=1900
.03x+2250-.0675x+0.025x=1900
-0.0125x=-350
x=28000@3%=840
z=14000@5%=700
the 4.5% is 8000=360
They add to 1900.
It can be done with x+y+z=50000
.03x+.045y+.05z=1900
but the way you used if you make y=50000-x-(1/2)x) is easier