A company produces a cleaning solution that has 60% concentration of Chemical K. The current production batch contains 200L of an ingredient with a 30% concentration of Chemical K and 150L of an ingredient with a 40% concentration of Chemical K. How much pure chemical K must be added to the batch to attain the correct concentration of Chemical K?

A. 150L
B. 175L
C. 200L
D. 225L
E. 250L

30% of 200 = 60L of K
40% of 150 = 60L of K

120L/350L

(120 + x)/(350 + x) = 60% = 3/5

600 + 5x = 1050 + 3x
2x = 450
x = 225

225L of K to be added.

Option D.

200*30%=60L chemical K
150*40%=60L chemical K
200+150=350L (concentration)

—> 60+60=120L —chemical K
350–120=230L —water

If you add the pure chemical K, the amount of total water cannot be changed in the concentration.
—> according to the question, the amount of water should be 40%:

230–>40%
x—> 100%

—> x= 100*230/40= 23*25=575
575–350=225L (pure chemical K)

The answer choice is D.

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200L of an ingredient with a 30% concentration of Chemical K = 30%of 200 = 60L
and 150L of an ingredient with a 40% concentration of Chemical K = 40% of 150 = 60L
_______
Total of Chemical K = 120L

And Total solution is now = 200L + 150L =350L
Now let X amount of Chemical K is added to above 120L of Chemical K ,which is required to be 60% of total solution

120+X = 60% of (350 + X)
120 + X = 3(350+X)/5
600 + 5X =1050+3X
2X= 450
X= 225L

Ans D