Question

2 litres of a liquid contains 60% alcohol. How much alcohol would be added to obtain a liquid containing 75% alcohol

Answer 1

Can we can assume we are adding 100% alcohol?

(.60 * 2 + 1.00x ) / ( 2 + x ) = .75

Answer 2

the numerator is pure alcohol, and the denominator is the liquid

Answer 3

dont quiteget it can u explain and not assume we are adding 100 alcohol

Answer 4

it doesnt tell you what percentage alcohol you are adding, so i assumed it was 100% alcohol

Answer 5

pure alcohol is 100% alcohol, im assuming

Answer 6

unless there is a typo in the question

Answer 7

It says adding alcohol, that is alcohol 100%

Answer 8

keep track of units, that is more important

Answer 9

i used the form

pure alcohol / total solution = 75%

Answer 10

\[\frac{ 1.2 L Alcohol }{ 2.0 L Liquid }\]

Answer 11

i divided each percent by 100 , to convert to decimal

Answer 12

yeah the equation is correct at the top, i'm just saying, the units are more important to keep track of, the numbers will fall out if you have your units end up correct.

Answer 13

as a general problem analysis

Answer 14

ok
( .60 * 2 liters alcohol + 1.00x liters alcohol ) / ( 2 liters liquid + x liters of liquid ) = .75

Answer 15

hard to fit in one line :)

Answer 16

Just the way i always did probs to make it easier

Answer 17

\[\frac{ 1.2 L Alcohol + x }{ 2 L Alcohol + x }= 0.75\]

Answer 18

@ganeshie8 do u have a simple solution ?

Answer 19

In the numerator we have 1.2 liters of alcohol , plus the x liters of 100% alcohol that you add.

Answer 20

Ima trying. If I let x = the amount of 75% solutionl....maybe it would be something like The water will be 25% of the solution. That means .8=.25x So the solution would be 3. 2 liters, and all additional solution would come from additional alcohol. I need to work on this more. I want to proof it to myself.

Answer 21

Hey I think your formulae will work.

Answer 22

75% of 3.2 would require 2.4 liters of alcohol, You already have 1.2 so you add 1.2 more. giving you 3.2 liter solution. In your formula what does x represents?

Answer 23

It also gives a value of 1.2 for x, Yours is simpler and straightforward. I now follow thanks.

Answer 24

The above was directed to @perl