SOLUTION: Concrete is made of cement, 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

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Question 1008633: Concrete is made of cement, 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!
Let n be your concrete. Then:
.60n+1(48-n)=.75(48)
.60n+48-n=36
.4n=12
n=12/.4=30
You need 30 kilos of 60% concrete mixed with 12 kilos of pure aggregate to make 42 kilos of 75% aggregate ☺