How many mL of 0.3 M HCl(aq) are needed to neutralize a 60 mL solution of 0.15 M Ba(OH)2?
Write the equation and balance it.
Determine mols of Ba(OH)2. M x L = mols.
Use the equation to convert mols Ba(OH)2 to mols HCl.
Then M x L = mols HCl.
You know mols and you know molarity, calculate L and change to mL.