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Recent problems solved by 'Masaries7'

Masaries7 answered: 3 problems
Mixture_Word_Problems/238584: I need help setting up the following word problem.
NOT LOOKING FOR THE ANSWER LOOKING FOR THE METHOD PLEASE.
How much pure acid should be mixed with 6 gallons of a 50% acid solution in order to get an 80% acid solution?
What I have is wrong I am sure:
.80=.50(x+6)+(x)
Any assistance would be greatly appreciated.
1 solutions

Answer 175274 by Masaries7(3) About Me  on 2009-11-13 13:59:23 (Show Source):
You can put this solution on YOUR website!
Your question consists of ratios.
.5(6)/6= 3/6 3 is the gallons of acid. 6 is the total gallons
To find out how much more gallons of acid you need to obtain 80% acid levels we add our unknown amount to bottom and top of the ratio indicating for the top more acid gallons and for the bottom more total gallons overall.
3+x/6+x= .8
Solve for 'x'
The format for this type of problem is to figure out your initial amounts then set up a ratio equaling the new desired percentage. You must be sure of how the information is applied in the problem for instance had we been adding non-acid solution then there would be no 'x' variable on the top since the ratio we have is acid gallons/ total gallons. Adding non-acid does not apply to acid. Good tip is to visualize the problem in your mind (if it's possible don't get brain freeze however)


Expressions-with-variables/234760: this is my problem. 19+x/2=4 because it's division i dont know how to solve. i dont understand to move the 19 over and move the 4 on the other side of the = sign. please help.
signed
below grade level.


1 solutions

Answer 173081 by Masaries7(3) About Me  on 2009-11-03 19:33:12 (Show Source):
You can put this solution on YOUR website!
Here's the problem restated: 19%2Bx%2F2=4
Step 1. Isolate the variable by it's self
19%2Bx%2F2-19=4-19+
on the left hand side the two "19"'s cancel becoming...
x%2F2=4-19
"4-19" equals "-15" so rewriting
x%2F2=-15
Step 2. Reverse whatever process is being done to "x" if "x" is being multiplied, you divide, if it's being divided, you multiply. etc
x%2F2=-15
multiply both sides by two
2%28x%2F2%29=2%28-15%29
The left hand side with "x" is being divided by "2" and multiplied by "2" these effects cancel each other out.
x=2%28-15%29
multiply the right hand side
x=-30
To check our answer we input the solution we concluded which was "-30" into the original problem which was 19%2Bx%2F2=4
19%2B%28-30%29%2F2=4
19%2B%28-15%29=4
19-15=4
4=4
Since we arrived at a mathematical truth (that "4" is indeed "4") the solution we concluded is indeed correct. It's my wish that you will be able to understand any type of problem of this manner. Please let me know if you have any further questions regarding this problem or any other math problem that's a puzzler for you.


Percentage-and-ratio-word-problems/234644: Will 12 1/2 minutes will be 12m 30secends or 12.5
1 solutions

Answer 173062 by Masaries7(3) About Me  on 2009-11-03 18:48:58 (Show Source):