Questions on Algebra: Systems of Linear Equations answered by real tutors!

Algebra ->  Algebra  -> Coordinate Systems and Linear Equations -> Questions on Algebra: Systems of Linear Equations answered by real tutors!     (Log On)
Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebra Solved!™: algebra software that solves YOUR algebra homework problems with step-by-step help!

   

Question 153663: A hospital staff mixed 70% disinfectant solution with a 30% disinfectant solution. How many liters of each were used to make a 30L of a 45% disinfectant
:
Let x = amt of 70% disinfectant
:
the resulting amt is to be 30L, therefore:
(30-x) = 30% stuff
: A hospital staff mixed 70% disinfectant solution with a 30% disinfectant solution. How many liters of each were used to make a 30L of a 45% disinfectant
:
Let x = amt of 70% disinfectant
:
the resulting amt is to be 30L, therefore:
(30-x) = 30% stuff

Answer by ankor@dixie-net.com(4531) About Me  (Show Source):
You can put this solution on YOUR website!
A hospital staff mixed 70% disinfectant solution with a 30% disinfectant solution. How many liters of each were used to make a 30L of a 45% disinfectant
:
Let x = amt of 70% disinfectant
:
the resulting amt is to be 30L, therefore:
(30-x) = 30% stuff
:
Write a decimal equation representing this problem
:
.7x + .3(30-x) = .45(30)
:
.7x + 9 - .3x = 13.5
:
.7x - .3x = 13.5 - 9
:
.4x = 4.5
x = 4.5/.4
x = 11.25L of 70% stuff required
then
30 - 11.25 = 18.75L of 30%
:
:
Check solution:
.7(11.25) + .3(18.75) = .45(30)
7.875 + 5.625 = 13.5; confirms our solutions