Your grandma needs your help. She has $70,000 to invest. Part of this money is to be invested in noninsured bonds with 16% annual interest. The rest of the money is to be invested in insured bonds with 6% annual interest. she told you that she requires a total of $9,900 per year from these invesetments. How much money should be placed in each investment?
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Need homework help on this problem: Grandma's investments
- Thread starter riechman
- Start date
Re: Need homework help on this problem
You need to set up a system of equations where x = part of the money and thus 70000-x equals the other part of the money call it y.
So x + y =70000 (represents total investment)
Now
to represent total interest use x(.16) + y(.06) = 9200
Solve this system using substitution or elimination or matrices.
You need to set up a system of equations where x = part of the money and thus 70000-x equals the other part of the money call it y.
So x + y =70000 (represents total investment)
Now
to represent total interest use x(.16) + y(.06) = 9200
Solve this system using substitution or elimination or matrices.
Re: Need homework help on this problem
When you use substitution you will use the fact that y = 70000-x to get just one variable
Like this
.16x +.06y = 9200 becomes
.16x + .06(70000-x) = 9200
so .16x + 4200 -.06x = 9200
now you jsut need to solve for x and that gives you that amount to invest at 16% plug it back into 70000 - x and get the amount to invest at 6%
When you use substitution you will use the fact that y = 70000-x to get just one variable
Like this
.16x +.06y = 9200 becomes
.16x + .06(70000-x) = 9200
so .16x + 4200 -.06x = 9200
now you jsut need to solve for x and that gives you that amount to invest at 16% plug it back into 70000 - x and get the amount to invest at 6%