A system of two euations in two unknowns

[sandra23860]

Please help me with this problem. I have to write a system of two equations in two unknowns for each problem. Sove by substitution. Thanks in advance for your help.

Mrs. Brighton invested $30,000 and received a total of $2,300 in interest. If she invested part of the money at 10% and the remainder at 5%, then how much did she invest at each rate?

 

[Guest]

First, decide what the two unknowns are.

 

[sandra23860]

The two unknown

The two unknown are elimination and substitution

 

[sandra23860]

The two unknown

Sorry for giving you the wrong information the two unknows are
x and y. Thanks for your help

 

[Guest]

The two unknown are elimination and substitution.

Those are two methods for solving systems of equations.

the two unknows are x and y.

Those are just names.

An "unknown" is a number that you do not know. You use a system of equations to solve for the unknowns.

So, what are the two unknowns in this problem? That is, what are the two numbers in this problem that we don't know and need to solve for?

 

[sandra23860]

The two unknown

This is all the book is giving me. I do not know the unknown. I thought it would be x and y.

 

[Guest]

I do not know the unknown.

You do not need to know their exact value yet. You do need to know what it is you are trying to find.

I thought it would be x and y.

What do "x" and "y" mean? The problem doesn't say anything about "x" or "y", so the problem has nothing to do with "x" or "y" unless you define "x" and "y" yourself.

The problem asks:

how much did she invest at each rate?

So what are the two numbers you need to find?

 

[sandra23860]

write a system of two equations in two unknowns for each

Ok this is it. I need to find out how much money Mrs. brighton invested at eacah rate of the $2300. How much she invested of the 10% and the remainder at 5%. I hope this is what you need. Thanks in advance for your help.

Mrs. Brighton invested $30,000 and received a total of $2300 in interest. If she invested part of the money at 10% and the remainder at 5% then how much did she invest at each rate?

for each problem. Solve by substitiution.( This is the rest of the subject. For some reason it would not let me complete the subject line.

 

[Guest]

How much she invested of the 10% and the remainder at 5%.

Right. Now name the unknowns.

Let x = dollars invested at 10%
Let y = dollars invested at 5%

Now find some equations in the problem.

Mrs. Brighton invested $30,000

There's one equation. Can you write it using x and y?

and received a total of $2300 in interest.

There's another equation. Can you write it using x and y?

 

[sandra23860]

solving the unknown

Thanks for your help.