Question 486990
I also have the same computation regarding the problem, mine goes like this..

let x=16%
    y=15%

   eq1 x+y =23000
       y =23000-x
   eq2 0.16x+0.15y =3500

perform the indicated operations in the equation:

      0.16x+0.15(23000-x)=3500
      0.16x+3450-0.15x=3500
      0.16x-0.15x=3500-3450
      0.01x/0.01x=50/0.01
      x=5000

     y=23000-5000
      =18000
therefore carla invested 5000 at 16%.
thank you...=)