You can
put this solution on YOUR website!I sympathise
If you don't get on the right track it can lead you in never ending circles
I try to write formulas that say exactly what the words say, only in algebra
I want a symbol for oil. O looks too much like zero, so
let Q = gallons of oil in the mixture
notice the amount of oil never changes in this problem
let G = gallons of gasolione I started out with
let X = gallons of gasoline I need to add to satisfy problem
now I can write equations
[1]
that's what the 1st sentence says
there are 3 gallons of this solution, so
[2]
now I have to add gasoline to make a new solution that is 5%
[3]
Q, the amount of oil doesn't change
I can substitute [2] direcly into [1]
solve for Q
substitute this value for Q in [2]
now use these values to solve for X in [3]
so, I have to add 1.8 gallons of gasoline to the mixture to get 5% oil
check
[3]
OK
another thing to check is, if you have 3 unknowns, you need 3 equations
if I didn't have 3 equations, I'd keep looking until I found them
