SOLUTION: A 10L tank of salt water is composed of 20% salt and 80% water. How many litres of salt water should be removed, and replaced with salt, so that the salt water consists of 30% salt

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Question 1084422: A 10L tank of salt water is composed of 20% salt and 80% water. How many litres of salt water should be removed, and replaced with salt, so that the salt water consists of 30% salt?
Answer by josgarithmetic(39614) About Me  (Show Source):
You can put this solution on YOUR website!
Remove 0.2x of salt and add or replace this with 1.0x of salt. The first term is amount salt as the 20% solution. The second term is pure undissolved salt.

%280.20%2A10-0.2x%2Bx%29%2F%2810-x%29=0.3-------------this is assuming no change of volume which could be the wrong assumption. Densities may also be important for the problem's description.