SOLUTION: please solve this problem. A certain concrete mixture contains 6.00% cement and 8.00% sand. How many kilograms of this mixture and how many kilograms of sand should be co

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Question 1054016: please solve this problem.
A certain concrete mixture contains 6.00% cement and 8.00% sand.

How many kilograms of this mixture and how many kilograms of sand should be combined with 235 kg of cement to make a batch that is 14.0% cement and 16.0% sand? Carry out all calculations exactly and round to three significant digits final answers only.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Thinking about a three-part mixture is more difficult than to think about a two part mixture.

s, how much of 100% sand;
235 kilograms, how much of100% cement;
m, how much of the "concrete" mixture at 6.00% cement and 8.00% sand.

These equations are using decimal numbers and not any quantities as percents:

Account for the desired percent cement.
%28235%2B0.06%2Am%29%2F%28235%2Bm%2Bs%29=0.14

Account for the desired percent sand.
%28s%2B0.08m%29%2F%28235%2Bm%2Bs%29=0.16


The arithmetic should be easier than to do the analysis shown, so you could take care of that arithmetic.