How much salt is in a mixture containing 10 gallons of an 11% salt solution and 6 gallons of a 7% salt solution? I think I can solve it but forming the equation is where I have problems.

Step-by-step explanation:

There really isn't an equation because there isn't an unknown. If we create a table, the "equation" that you are talking about will be come apparent. Let's call the 2 solutions Sol 1 and Sol 2:

                      Gallons of solution    *        % salt          =         Gallons of salt

Sol 1  

Sol 2

If we fill in this table according to the info we are given, we have 10 gallons of the 11% solution, and 6 gallons of the 7% solution, so

                     Gallons of solution       *       % salt         =        Gallons of salt

Sol 1                        10                                     .11            =        1.1 gallons of salt

Sol 2                        6                                     .07           =        .42 gallons of salt

We multiply the Gallons of solution by the % salt to get the gallons of salt. There are 1.1 gallons of salt in solution 1 and .42 gallons of salt in solution 2, so in the mixture (which is 16 gallons) there is 1.1 + .42 gallons of salt, which is 1.52 gallons of salt.