How many $\sigma$ and $\pi$ bonds are present in each of the following molecules?
$(a)$ $HC \equiv C-CH=CH-CH_3$
$(b)$ $CH_2=C=CH-CH_3$

(N/A) For $(a)$ $HC \equiv C-CH=CH-CH_3$:
Total $\sigma$ bonds = $4$ ($C$-$C$) + $6$ ($C$-$H$) = $10$ $\sigma$ bonds.
Total $\pi$ bonds = $2$ ($\pi$ in $C \equiv C$) + $1$ ($\pi$ in $C=C$) = $3$ $\pi$ bonds.
For $(b)$ $CH_2=C=CH-CH_3$:
Total $\sigma$ bonds = $3$ ($C$-$C$) + $6$ ($C$-$H$) = $9$ $\sigma$ bonds.
Total $\pi$ bonds = $2$ ($\pi$ in $C=C=C$) = $2$ $\pi$ bonds.