Question 757300: A store mixes Brazilian coffee worth $12 per kilogram and a Turkish coffee worth $15 per kilogram. The mixture is to sell for $13 per kilogram. find how much of each should be used to make a 120 kilogram mixture.
Answer by Clarmenselda(1)   (Show Source):
You can put this solution on YOUR website! to solve this problem you much first make an equation to match. SO, let's start with that.
We want Brazilian coffee(which we'll call BC) plus Turkish Coffee(which we'll call TC) to equal a new type of coffee (which we'll call BTC.
So,
BC + TC = BTC
now, BC is 12.00/kilogram, and we don't know the weight so x will represent the weight. So far, we've got 12x now the BTC weighs 120k, so we need to fix our equation to be 12(x+120)
now for TC. this is almost the same as BC, except that it costs more. So, TC is 15(x+120).
Remember that we want to add BC to TC. So far we have:
12(x+120)+ 15(x+120)
All that's left now is BTC and solving! BTC is easy, because we know the weight. So, we just need to do this: 13(120) the final problem is:
12(x+120)+15(x+120)=13(120)
let's solve the right hand side first. 13 times 120 is 1560, so now our problem should look like this:
12(x+120)+15(x+120)=1,560
Next, using the distributive property, it'll become:
12x+1,440 + 15x + 1,800=1,560
Rearanging:
12x+15x+1,440+1,800=1560
Simplifying:
27x +3,240 =1560
now, to solve for X we must subtract 3240, but we must subtract it from both sides, which leaves us with:-1,680
our problem should look like this:
27x= -1,680
Dividing leaves us with:
-62
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