In your case, an ammonia solution that is
This means that you can essentially use the solution's percent concentration as a conversion factor to help you go from grams of solute to grams of solution or vice versa.
In your case,
#135 color(red)(cancel(color(black)("g solution"))) * overbrace("12.5 g NH"_3/(100color(red)(cancel(color(black)("g solution")))))^(color(purple)("= 12.5% m/m")) = color(green)(|bar(ul(color(white)(a/a)"16.9 g NH"_3color(white)(a/a)|)))#
The answer is rounded to three sig figs.
Now, you can use the exact same approach to find the volume of fruit juice present in
This time, you're dealing with percent concentration by volume, or
Use this concentration as a conversion factor to get the answer. You should end up with