Question

There are two solutions being mixed by a chemist. The first consists of 35% iodine and the second consists of 40% iodine. How many liters of the first solution will be needed for a 15–liter mixture that is 36% iodine?

10
12
3
5

Answer 1

i know
\[a+b=15\]
and
\[.35a+.40b= ...?\]

Answer 2

@UnkleRhaukus

Answer 3

My first instinct is that your second equation should be \(.35a + .40b = .36(a+b).\)
But I might need to think on it a bit.

Answer 4

is that right @nincompoop

Answer 5

http://www.wolframalpha.com/input/?i=a%2Bb%3D15%2C+.35a%2B.40b%3D.36a%2B.36b

Gives
a=12
b=3

Try to check yourself.

Answer 6

Okay, on second thought, I as correct.

The first equation represents the total liters.

The second equation represent the iodine liters.

Does that make sense? @yummydum

Answer 7

i get it :)

Answer 8

there we go!!

Answer 9

thanks nin! :D