Question

Solve this word problem. Please help!


A cosmetologist has a bottle of 7% hydrogen peroxide solution and a bottle of 4% hydrogen peroxide solution. The cosmetologist needs 300 milliliters of a 5% hydrogen peroxide solution for a hair dye. Write and solve a linear system to find how many milliliters of each solution the cosmetologist needs to mix together.

Answer 1

@jdoe0001

Answer 2

@zepdrix

Answer 3

So what do you think the important information is?

Answer 4

the percentages
7% 5% 4%

Answer 5

are you going to say something or sit there and make me feel like an idiot.

Answer 6

what else is important?

Answer 7

i don't know! I wouldn't be here if i did!

Answer 8

Well, what number haven't you said that is in the problem. That is usually the easiest way to find the important bits

Answer 9

300 is the only other number but they don't tell you how many milliliters the other bottles are. so i don't see how that can be useful.

Answer 10

"they don't tell you how many milliliters the other bottles are"
What do we do in math when they don't tell us something?


I like to call this first part the Given. So we have as our givens.
A 7% sln.
A 4% sln.
300 ml total
a 5% sln

Answer 11

Now, we need to answer the question, what do they want us to find?
So, what is the goal of this problem? What are they asking us for?

Answer 12

how many milliliters are in the 5% solution

Answer 13

so let's start with, when we don't know how much they have of the other two solutions part.
what do we use in math when let's say we don't know how many ml of a 4% sln we need?

Answer 14

hint: Think about things you find in the eq. of a line.