dam word problems

G

Guest

Guest
a 60% sulphuric acid sulution will be mixed with a 95% sulphuric acid solution to produce 2700ml of a 70% solution. how much of each will be used?
 
It is the same as the last problem.
H is .95
L is .6
Total is 2700ml of .7
Try to finish it.
 
brandon21 said:
a 60% sulphuric acid sulution will be mixed with a 95% sulphuric acid solution to produce 2700ml of a 70% solution. how much of each will be used?

Let x = number of ml of 60% solution
The amount of acid here is 0.60x

We're supposed to end up with 2700 ml, so there must be 2700 - x ml of 95% solution.
The amount of acid here is 0.95(2700 - x)

At the end, we will have 2700 ml of 70% solution, which contains 0.70(2700) ml of acid.

acid in 60% solution + acid in 95% solution = acid in 70% solution
0.60x + 0.95(2700 - x) = 0.70(2700)

You can take it from here.
 
Little "trick" I use, brandon (quantities on left, percentages on right):
Code:
  x   : a
  y   : b
=========
 x+y  : c
ax + by = c(x + y)
 
One way to look at it is to think of how much acid is 70% of 2700

That's 1890 ml.

So we have, \(\displaystyle .60x+.95y=1890\)

How much total solution?:

\(\displaystyle x+y=2700\)

So, you have two equations:

\(\displaystyle .60x+.95y=1890\) acid
\(\displaystyle x+y=2700\) total solution

Solve the bottom one for y and sub into the first and you have the equation Mrspi gave you. See how it works?.
 
No one has said it but they're using it: amount = concentration times volume.
 
Top