How many quarts of pure antifreeze must be added to 6 quarts of a 10% antifreeze solution to obtain 60% antifreeze solution?

Let x be the number of quarts of pure antifreeze solution that is to be added
Let x be the number of quarts of pure antifreeze solution that is to be added
x quarts of pure antifreeze(100%) + 6 quarts of 10% antifreeze = (x+6) quarts of 60% antifreeze
x(1) + 6(0.1) = (x+6)0.6
x+0.6 =...