Question 1182613
Use  42% acid and 18% acid solutions to make 32 mL. of 30%.


If v mL. of 42%, then to account for pure acid,
{{{42v+18(32-v)=30*32}}}
and solve for v.



Be aware that  {{{(42+18)/2=30}}}, so the student will need 16 mL. of each of the starting solutions of acid.