SOLUTION: Kayla and her brother mixed together some soil and some silt to make 12 m^3 of soil with a 75% silt content. They used 7 m^3 of silt and 5 m^3 of a soil they purchased. What was th

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Kayla and her brother mixed together some soil and some silt to make 12 m^3 of soil with a 75% silt content. They used 7 m^3 of silt and 5 m^3 of a soil they purchased. What was th      Log On

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Question 939697: Kayla and her brother mixed together some soil and some silt to make 12 m^3 of soil with a 75% silt content. They used 7 m^3 of silt and 5 m^3 of a soil they purchased. What was the silt content of the soil they purchased?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let the m^3 of silt in the soil they purchased = +x+
Total amount of silt in their mix = +7+%2B+x+
-----------------------
+%28+7+%2B+x+%29+%2F+%28+7+%2B+5+%29+=+.75+
+7+%2B+x+=+.75%2A12+
+7+%2B+x+=+9+
+x+=+2+
There is 2 m^3 of silt in the 5 m^3 soil they purchased