Question

How many liters of pure alcohol must be added to 40 liters of 20% alcohol solution to obtain a mixture which is 25% alcohol?

Answer 1

a + 40 = t *(-1)
a(1) + 40(.2) = t(.25)
--------------------


-a +40(-1) = t(-1)
a + 40(.2) = t(.25)
-------------------
40(.2-1) = t(.25-1)

40(-.8)
------ = t
(-.75)

a = t-40

and i prolly messed it up along the way while trying to be coy lol

Answer 2

prolly could have gone the easier route and *-.25 on top to just solve for a :)

Answer 3

8/3 liters?

Answer 4

a + 40 = t *(-.25)
a(1) + 40(.2) = t(.25)
--------------------


a(-.25) +40(-.25) = t(-.25)
a (1) + 40(.2) = t(.25)
-----------------------
a(1-.25) +40(.20-.25)=0

a(.75) =40(.25-.20)


40(.25-.20)
a = -----------
.75

Answer 5

8/3 is what i get too :)

Answer 6

One can simply solve for \( x \) in
\[ (8+x) =(40+x) \times 0.25 \]

Answer 7

\[\frac{8}{3}=2+\cfrac{2}{3}\to 2+\cfrac{1}{\cfrac{3}{2}}\to 2+\cfrac{1}{1+\cfrac{1}{2}} \]
\[[2;1,2]\]as a continued fraction :)

Answer 8

Yeah sure, @amistre64 is known for his cryptic approaches lol

Answer 9

100% L + 20% 40 = 25% ( L + 40)
-> L + 8 = L/4 + 10
-> 3L/4 = 2 => L = 8/3 litter pure alcohol

Answer 10

kitty litter ... ewww!!!

Answer 11

Hey, I guess I'm obsessed with my kitty :")