Question

A man invests $20,000 to yield $1,280 interest annually.If part of his investment pays 6% annually and the rest of his investment pays 7% annually,how much does he invest at each rate?

Answer 1

we need a variable for the amount invested at say 7%
you pick it

Answer 2

it doesn't matter what you pick, so pick any letter you like

Answer 3

idk that's the problem i don't understand the question

Answer 4

i will walk you through it

Answer 5

we need two numbers, the amount invested at 7% and the amount invested at 6%
to do a problem like this, you need to have a variable representing some number you want,
then you need an equation to solve
but the first step is to make a variable
you pick it

Answer 6

pick some letter to represent the amount invested at 7% interest

Answer 7

you can pick such your smart and you know what your doing

Answer 8

there are 26 letters in the alphabet, you do not need to be smart to pick one of them

Answer 9

just asking are you a boy or girl?

Answer 10

also there is the greek alphabet, you can pick a letter from there too
the indians used colors for there variables

Answer 11

HI!!

Answer 12

why don't you pick \(x\) that is what the math teachers usually use

Answer 13

ok \(x\) it is
then if the amount invested at 7% is \(x\) and the total is \(20,000\) then the amount invested at 6% is \(20,000-x\)

Answer 14

then

Answer 15

7% of \(x\) is \(0.07x\) right?
at 6% of \(20,,000-x\) is \(.06(20,000-x)\)

Answer 16

yes, and since the total interest is 1280 you know that
\[.07x+.06(20,000-x)=1280\]

Answer 17

final job is to solve that for \(x\)

Answer 18

yeah but decimals are so annoying

Answer 19

k lets get rid of them by multiplying both sides by 100 to clear the decimals

Answer 20

oh ok, then we can just solve
\[7x+6(20,000-x)=128,000\]

Answer 21

yeah if you multiply both sides by 100 the decimal goes, and of course you have to multiply \(1280\times 100\) to get \(128,000\)

Answer 22

now it should be easy right? distribute the 6
then combine like terms
then you can solve for \(x\) in one step

Answer 23

so x is suppose to equal to?

Answer 24

you still have to find \(x\) by solving \[7x+6(20,000-x)=128,000\]

Answer 25

i mean how much does he invest at each rate?

Answer 26

solve for \(x\) and you will know how much is invested at 7%
do you know how to do that?

Answer 27

no

Answer 28

its all too confusing

Answer 29

then skip it
you need to know how to solve basic linear equations first before you can worry about complicated word problems

Answer 30

but its homework and i need to finish it,its due tomorrow that's why i need help to find what x is

Answer 31

Well, let's see what we can do ^^
Do you know what "distribute" means in this context?

\[7x+\color{red}6(\color{blue}{20,000}-\color{green}x)=128,000\]

Answer 32

it is too confusing
go back and learn how to solve linear equations first
then you need to know how to set up a word problem
finally you can tackle something like this
there is not royal road to algebra, you have to do it step by step

Answer 33

Miss Tea scared her off D:

Oh noes

Answer 34

any one who starts of with "i don't get it" "this is too confusing" "this doesn't make sense" is not ready to begin a problem like this
you could go ahead and give the answer, but it will make no sense at all
look at all the work we did just to set up the equation
need to go back and learn the basics, then we can tackle something like this

Answer 35

Aww, there's no need to get so extreme ^^

Come on, @vickie11223
work with me here. What I want you to do is distribute the 6 to the two terms inside the parentheses.

What that means is you multiply 6 to those two terms.

Can you do that?

\[7x+\boxed{6(20,000-x)}=128,000\]
Focus on the stuff in the box first.

Answer 36

yes