if I have 120 gals of fluid that is 20% alcohol how much fluid of 70% alcohol would I have to Add to the 120 gal to make it 40% alcohol
2007-03-14 04:11:45 · 3 answers · asked by Bernie A 1 in Science & Mathematics ➔ Chemistry
let the # of gals of 70%alc. be x
now we have 120+x gals for 40% of alc.
so we have a eq.
20% of 120gals + 70% of x gals = 40% of (120+x)gals
=> 20/100 *120 + 70/100 * x = 40/100 * 120+x
=> 2400+ 70x = 4800 + 40x
=> 30x = 2400
=> x = 80 gals
hence 80 gals is the answer
2007-03-14 04:28:44 · answer #1 · answered by ctenophora 2 · 0⤊ 0⤋
suppose the result is x. After addition , volume is 120+x
you can make an equation in%
120*20+ 70x = 40 (120+x)
2400+70x = 4800 +40x
30x = 2400
ANSWER x=80
2007-03-14 04:34:05 · answer #2 · answered by maussy 7 · 0⤊ 0⤋
Assuming that the volume of the mixture isn't subject to concentration:
120gl * 20% + X gl * 70% = (120+X) gl * 40%.
Resolve for X:
X gl *(70% - 40%) = 120 gl * (40% - 20%)
X = 120 gl * 20%/30% = 80 gl.
2007-03-14 04:32:54 · answer #3 · answered by jorganos 6 · 0⤊ 0⤋