Question 157631

I AM ASSUMING THAT THE "i" SHOULD BE A "1"

Let x=amount of water needed

Now we know that the amount of pure antifreeze that we have before the water is added (1 gal) has to equal the amount of pure antifreeze that we have after the water is added(0.60(1+x)).  So our equation to solve is
1=0.60(1+x)  get rid of parens
1=0.60+0.60x  subtract 0.60 from each side
1-0.60=0.60-0.60+0.60x collect like terms
0.40=0.60x  divide each side by 0.60
x=2/3 gal-------------------------amount of pure water needed

CK
1=0.60(1 2/3)
1=0.60(5/3)
1=0.20*5
1=1


Hope this helps---ptaylor