this much diff. question can come in GMAT?

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by Night reader » Mon Dec 13, 2010 12:25 pm
towerSpider wrote:A pool inspector pours 2 liters of a 16% chlorine solution into 6 liters of a 20% chlorine solution. How many liters of the resulting solution must she add to 1 liter of a 30% chlorine solution to create a solution that is 24% chlorine?
ok now - find solution S
2 lt 16% => 0.16*2
6 lt 20% => 0.20*6
-------------------------
8 lt x% => (0.32+1.2)

S*(0.32+1.2)/8 + 0.30/1= (S+1)*0.24/1
S*1.52 + 8*0.30= 8*(S+1)*0.24
8*0.30 - 8*0.24= S*8*0.24 - S*1.52
8*0.06= S*1.92 - S*1.52
8*0.06=S*0.40
S= 8*0.06/0.40 => 8*(6/100) : 40/100 = (48/100) * (100/40) = 48/40 or 6/5 lt.
answer: 1 1/5 lt.