Question 924778
We have 40 liter of 85% solution
We want to add some 100% solution  to make   95% solution
1*x+0.85*40=0.95(40+x)
1*x+34=38+0.95x
1x-0.95x=38-34
0.05x=4
x=80 liter at 100% (80) is added to 40 liter at 85%(34) to make 95% of 120 liter(114)
check
1*80+0.85*40=0.95(40+80)
80+34=0.95(120)
114=114
ok
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