which batch to make 60...ambiguity in question

in the premise, one batch is mentioned,
and that batch is formed of adding two different concentrations: 200L of 30% K and 150L of 40% K

Conc. 1:
K:Water:total
30:70:100 (ratio)
60:140:200 (L)

Conc. 2:
K:Water:total
40:60:100 (ratio)
60:90:150 (L)

so by adding, K:Water:total = 120:230:350 (L) --> which is the final form of the current batch

to convert it to 60% by adding x (L) of K,
\(\frac{120+x}{350+x}\) = \(\frac{60}{100}\),
and x = 225L
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We can create the equation:

(200 x 0.3 + 150 x 0.4 + K)/(350 + K) = 0.6

(60 + 60 + K)/(350 + K) = 3/5

5(120 + K) = 1050 + 3K

600 + 5K = 1050 + 3K

2K = 450

K = 225

Alternate Solution:

We have 200 liters of 30% solution and 150 liters of 40% solution, and we will add x liters of 100% solution, thus obtaining (200 + 150 + x) liters of a 60% solution. We can summarize this in the following equation:

200(0.30) + 150(0.40) + x(1.00) = (200 + 150 + x)(0.60)

60 + 60 + x = 120 + 90 + 0.6x

120 + x = 210 + 0.6x

0.4x = 90

x = 225 liters

Answer: D
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