SOLUTION: Concrete is made of cement, water, and aggregate (sand and gravel). Aggregate should make up 75% of the total mass of concrete. If you have a concrete mix that is 60%aggregate, how

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Question 1008357: Concrete is made of cement, water, and aggregate (sand and gravel). Aggregate should make up 75% of the total mass of concrete. If you have a concrete mix that is 60%aggregate, how many kilograms of this mix and how many kilograms of aggregate should be combined to form 48 kilograms of the concrete mix with the proper percentage of aggregate?
Answer by jorel555(1290) About Me  (Show Source):
You can put this solution on YOUR website!
Assuming the aggregate is pure 100% aggregate, then let x be the amount of 60% aggregate you start with. Then:
.6x+1(48-x)=48(.75)
.6x+48-x=36
12=.4x
x=12/.4=30
30 ks of 60% aggregate mixed with 18 ks of pure aggregate make 48 ks of 75% aggregate!!!!!!!