Your supplier only ships acid solution in 7% and 15% concentrations. How many liters of the 7% solution should you mix to obtain 8 liters of 10% solution?

Question

anonymous · Answer

You need to mix 5 liters of the 7% solution. :'D

amistre64 · Answer

acid@7% = 8(.10-.15)/(.07-.15)

amistre64 · Answer

5 is good :)

amistre64 · Answer

assuming of course that your mixing the 2 together

anonymous · Answer

If you need the equation I used, it's
7x + 15(8-x) = 80
: )

amistre64 · Answer

oh i used it to; but more condensified ;)

anonymous · Answer

Lol, yes. :D

anonymous · Answer

how can i write this out. like show work

amistre64 · Answer

depends on how you want to solve it ...

usually the long way is to make equations that relate and either sub or eliminate to get to the answer

amistre64 · Answer

a   +  b =t     ; *-x
ax + by = tz

-ax -bx =-tx 
  ax +by = tz
------------
    b(y-x) = t(z-x)

   b @ y% = t(z-x)/(y-x)

anonymous · Answer

woah just the simple way please. using actual numbers

anonymous · Answer

Let x= liters of 7% sol'n
8-x = liters of 15% sol'n

7x + 15(8-x) = 10(8)
Solve for x. : )

You can always use put the percents in decimal or fraction form, but I always find it easier to do it using whole numbers.

amistre64 · Answer

lol ... 

  a     +    b     = 8          ;*-.15
a(.15) + b(.07) = 8(.10)

-a(.15)  + b(-.15) = 8(-.15)
  a(.15) + b(.07)    = 8(.10)
------------------------
            b(.07-.15) = 8(.10-.15)

            amount @ 7% = 8(.10-.15)/(.07-.15)