Interpreting a balanced chemical reaction - class-IX

0.05 mole of $LiAlH _4$ in ether solution was placed in a flask containing 74g (1 mole ) of t-butyl alcohol.The product $LiAlHC _{12}H _{27}O _3$ weighed 12.7 g. If Li atoms are conserved, the percentage yield is : (Li=7, Al=27, H=1, C=12, O=16).