Question 716996
This chemist wants a more concentrated solution of sulfuric acid than the 25% concentration reported available in the description.  This chemist should have 96% or 98% sulfuric acid present, otherwise cannot make the 40% concentration which is wanted.  


Does this person have maybe 50% sulfuric acid present?
x for how much 25%, y for how much 50%.

Still, there would be too much difference in densities.  Volume units used for measurement? Assuming the concentrations are by volume, %w/v,
{{{(25x+50y)/500=40}}} and {{{x+y=500}}}.
Solve for x and y.