The number of hybrid orbitals and pure orbitals involved in bonding in ${\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{CH}$ molecule are
 

No.of hybrid orbitals = Sum of the hybrid orbitals at all carbons = 4x No.of  sp3 carbons + 3XNo. of sp2 carbons+ 2XNumber of  of sp carbons

No of H.O's = (4X1) + (2X2) = 8

No. of pure orbitals = Sum of number of atoms other than carbons + 2X No. of π
bonds

No of P.O = 4 + (2X2) = 8