Homework Help: Algebra

Posted by Becca on Monday, December 7, 2009 at 8:41pm.

I have 2 questions in math that I am not quite sure about...

1. Mandy begins bicycling west at 30 mph at 11 A.M. If Liz leaves from the same point 20 min. later bicycling west at 36 miles per hour, when will she catch Mandy?

2. A mixture of 10% acid and 90% water is added to 5 liters of pure acid. The final mixture is 40% water. How many liters of water are in the final mixture?

thanks:)

Algebra - drwls, Monday, December 7, 2009 at 9:58pm
1. Write equations for distance traveled vs. the time after 11 AM. Set them equal and solve for t.
M = .5 t (if t is in minutes)
L = .6 (t -20)
M = L when 0.5t = 0.6t -12
0.1t = 12
t = 120 minutes (after 11 AM), which is 1:00 PM

2. Assume X liters of 10/90 mix are added
Liters of acid in mix = 0.1X + 5
Liters of water in mix = 0.9X
Total volume of mix = 5 + X

Solve 0.4 = 0.9X/(5+X)
2 + 0.4X = 0.9X
X = 4
90% of X is the amount of water

Answer this Question

Related Questions

Algebra - I have 2 questions in math that I am not quite sure about... 1. Mandy ...
Math Rates/proportions - I have two questions that are based on the following ...
Science - Hi, I have two questions about biology I need help with. 1) Some ...
Ella Minnow Pea - I read the book Ella Minnow Pea for school... And I actually ...
Calculus - (Another related rate question) A plane (alt. 4000ft) is flying west ...
8th Grade English - My teacher for my english class at school marked off for ...
Drbob222 - Can you please help me with some questions I have on my Chemistry lab...
math - distance from A-B is 40 km.Mandy starts from A at 11 am and Jason starts ...
algebra - each week, mandy's algebra teacher gives a 10 point math quiz. ...
I HAVE A MATH TEST TOMORROW HELPPP PLEASE! - im not sure how to find the first ...

For Further Reading

First Name:
School Subject:
Answer: