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math problem

A health clinic uses a solution of bleach to sterilize petri dishes in which cultures are grown. The sterilization tank contains 100 gal of a solution of 2% ordinary household bleach mixed with pure distilled water. new research indicates that the concentration of bleach should be 5% for complete sterilization. How much of the solution should be drained and replaced with bleach to increase the bleach content to the recommended level?

oh pack this is a hw question? i'll holla back later

hehe i'll try to get my dad to figure it out ^^

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ok this is purely my dad's doing......sorry if it's wrong

2 gallons + x = 0.05
100 - x

solve the equation.....by cross multiplying

sorry that probably didn't help much

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if it's one hundred gallons, 2% would be 2 gallons. So assuming you can drain only water away from the solution, it'd be to drain 3 gallons of water and put in 3 gallons of bleach. This was simple, so it's probably not right, though it could be

why don't they just make a new solution of bleach without draining the whole thing?

lemme explain my problem too

since 2% of 100 gal is 2gal, you have x amount you need to make it 5% solution so it would be 2gal plus the x amount to get it to five percent....

and you gotta put that over a 100 take away the x amount that is needed to be put into the solution

and the fraction of that should make 5%......

oy, this is giving me a headache....i hope you understand what i'm trying to say

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If it should be "5% concentration" instead of "two",
you should try to multiply the amount of 100 gallons to the two percent or 0.02 (2% in decimal form).
Then, equate the following so that you have a five percent concentration for the 100 gallons of "solution". (Solution stands for 'sum', or the distilled H2O added to the amount of household bleach.
In the end, the point of the procedure is to have a certain concentrate of the bleach, so that sterilization is possible without wasting too much bleach or unnecessary sterilization.
Do you get that? Hope that helped out a little...

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