How many grams of caso4 (molar mass = 136 g) can be produced if 15.4 g ca3(po4)2 (molar mass = 310 g) completely reacts?

Balance Chemical equation is as follow,

                    Ca₃(PO₄)₂  + 3 H₂SO₄   →   3 CaSO₄  +  2 H₃PO₄

According to eq.

     310 g (1 mole) of Ca₃(PO₄)₂ produces  =  408.42 g (3 mole) of CaSO₄
So,
              15.4 g of Ca₃(PO₄)₂ will produce  =  X g of CaSO₄

Solving for X,
                                           X  =  (15.4 g × 408.42 g) ÷ 310 g

                                           X  =  20.28 g of CaSO₄

The answer is b on plato.