math quest...

[xoangelxo]

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What is the quickest way to do this problem? Thanks.

In a barrel there are 60 pints of a solution that is 20% alcohol. How many pints of pure alcohol must be added to produce a solution that is 40% alcohol?

 

[thefifthbeatle]

What is the quickest way to do this problem? Thanks.

In a barrel there are 60 pints of a solution that is 20% alcohol. How many pints of pure alcohol must be added to produce a solution that is 40% alcohol?

Although I am 99.999999999% sure this is wrong, the M1V1=M2V2 sticks out as the quickest.......Is the answer 30?

DISREGARD EXPLANATION--check below

 

[xoangelxo]

the answer is suppose to be 20 pints...

 

[thefifthbeatle]

Okay, sorry I made a mistake above

This is the equation I came up with

(60)(.20) + (1.00)(x) = (.4)(x+60)

You get 20

It goes like this

at first, you have 60 pints and 20% alcohol (60)(.20)
you are adding 100% with unknown volume (1.00)x
and you want it to equal 40%...The volume will be the unknown plus the original 60


Unfortunately, there really is no quick way to do this, you just gotta think for a little..and with the DAT we don't have all that time