a 20*/* phosphoric acid solution has a density of 1.14g/ml.calculate the molality and molarity of the solution.

Is 20*/* the same as 20%? Is that w/w% or something different. I will assume w/w.

1.14 g/mL x 1000 mL x 0.20 = ?g H3PO4.
mols H3PO4 = ?g/molar mass and that is the molarity since M = mols/L soln.

m = mols/kg solvent. mols is same as above.
g soln = 1.14 x 1000 = ?g
g H3PO4 you have above.
g solvent = ?g soln-g H3PO4 = x. Convert to kg and solve for m.