Question 886466
You may need to know the density of the 5% solution to do this right, and maybe need to know how the percent concentrations are expressed regarding mass/vol or mass/mass.


An estimation can be made using these as a system:


{{{(2*u+5*v)/40=3}}} and {{{u+v=40}}}


u = volume of 2%
v = volume of 5%