Question 771698
Hi, 
I specialize in mixture problems. You can 
click on " our tutors " , and I am close to the 
top of the list- Josmiceli.
Look for solutions to mixture problems
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From an understanding point of view, you are
given some 20% mixture and some 50% mixture. 
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Then you are told that you have to end up with 
a certain quantity of 30% mixture, for example.
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Note that the % that you end up with has to be
between 20% and 50%, or it can't be solved
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Pay attention to units. The answer is usually in
the same units, like gallons.
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Right away, assign letters to the unknowns.
That helps to get it down right away, like:
Let {{{ a }}} = gallons of 20% mixture needed
Let {{{ b }}} = gallons of 50% mixture needed
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Then, you are usually able to make two more statements:
{{{ .2a }}} = gallons of concentrate ( acid or whatever ) in 20% mixture
{{{ .5b }}} = gallons of concentrate in 50% mixture
Get this down right away
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Then, usually, you are able to say:
{{{ a + b }}} = the given final quantity in gallons or whatever
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Then you can say:
{{{ ( .2a + .5b ) / ( a + b ) = .3 }}}
That's all you need to solve problem. Note that {{{ a + b }}}
is given .
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Hope this helps. Go for easier ones and work up to harder ones