A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 4 years ago
Show an equation and a solution for the problem. Arnold needs a 25% solution of nitric acid. He has 20 milliliters (ml) of a 30% solution. How many ml of a 15% solution should he add to obtain the required 25% solution?
anonymous
 4 years ago
Show an equation and a solution for the problem. Arnold needs a 25% solution of nitric acid. He has 20 milliliters (ml) of a 30% solution. How many ml of a 15% solution should he add to obtain the required 25% solution?

This Question is Closed

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0ok he currently has 20 mg at 30% for a total of \[.3\times 20=6\] mg of acid. lets say he adds "x" mg or 15% solution. then the total amount of solution he will have is \[30+x\] and the "x" mg of 15% solution will contribute \[.15x\] acid. so he will have a total of \[6+.15x\] acid, and a total of \[30+x\] solution. now he wants that solution to be 255 acid, i.e. he want the total amount of acid to be \[.25(30+x)\]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0now that we have two expressions for the amount of acid he wants, we can set them equal and write \[6+.15x=.25(30+x)\] and solve for x

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0if you need help solving let me know, but i would get rid of the decimals first by multiplying both sides by 100 to write \[600+15x=25(30+x)\]and work with whole numbers instead of decimals

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0okay thank you i really needed that i understand now.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0and i see that i made a mistake, hold on a second

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0oh because i wasn't paying attention. he has 20 mg of 30% solution so the total amount is \[20+x\] not what i wrote. equation should be \[6+.15x=.25(20+x)\] i put a 30 instead of a 20

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0sorry about that. solve \[600+15x=25(20+x)\]and you will get the answer. let me know if you have trouble but usually setting up the equation is the hard part, solving is the easy part
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.