Answer:
x = 1.5 gallons.
Step-by-step explanation:
Let x = the required number of gallons of pure juce (100% juice) to be added to the 6 gallons of 50% juice mixture.
0.5(6)+x = 0.6(x+6) Simplify.
3+x = 0.6x+3.6 Subtract 0.6x from both sides.
3+0.4x = 3.6 Subtract 3 from both sides.
0.4x = 0.6 Finally, divide both sides by 0.4
x = 1.5 gallons.