Question

Please Answer This Someone i Really dont Understand...
how many grams of an 18%saline solution and how many grams of a 45% saline must be mixed to create 2700 grams of a 25% saline solution..

Answer 1

First define your variables

Answer 2

How many variables are we dealing with?

Answer 3

i think 2...

Answer 4

good, so let's use the variables x and y

Answer 5

we have 2 unknown amounts of solution

a) the 18% solution

b) the 45% solution

agreed?

Answer 6

Yup

Answer 7

so let x = amount of 18% solution and y = amount of 45% solution

both amounts are in grams

Answer 8

ok

Answer 9

it says

"must be mixed to create 2700 grams of a 25% saline solution"

so there is a total of 2700 grams of this solution

What does that mean in terms of x and y?

Answer 10

i wrote out the eaquation in this stupid box paper thing the teacher gave me .. and i came up with .18x+.45x=675

Answer 11

that's close to one of the equations

Answer 12

so i was almost right?

Answer 13

yes not quite correct though

Answer 14

dang..

Answer 15

this is why the definitions help

remember we let

x = amount of 18% solution and y = amount of 45% solution

Answer 16

yeah but there were 2 x's

Answer 17

which is why it's wrong

Answer 18

ha never mind blonde moment (:

Answer 19

its ok

Answer 20

what's the correct equation

Answer 21

idk thats why i neede help.......

Answer 22

need*

Answer 23

y corresponds to the 45% solution, so it should be 0.45y NOT 0.45x

Answer 24

o

Answer 25

also, you know there is a total of 2700 grams, so the two amounts (x and y) must add to 2700


so...

x+y = 2700

Solve for y to get

y = 2700 - x

Answer 26

making sense so far?