Taking logs of Y=K0.33(AL)0.67 and differentiating with respect to time gives the growth-accounting decomposition:
gY=0.33gK+0.67(gA+gL)
where gA+gL combines because A and L enter the production function jointly as the single composite term (AL), so their growth rates add before being weighted by the 0.67 exponent.
Substituting the given growth rates (gK=3%, gA=1.5%, gL=1.2%):
gY=0.33(3)+0.67(1.5+1.2)=0.99+0.67(2.7)=0.99+1.809=2.799
Therefore the growth rate of Y is approximately 2.80% per annum, within the key's accepted range of 2.70 to 2.90.