The number of geometrical isomers possible for the compound, CH_3...

Although $\mathrm{CH}_3$\mathrm{C}=\mathrm{CH}$-$\mathrm{CH}=\mathrm{CH}$_2$ has two double bond but one of them has two similar atoms (i.e. H -atom) therefore no geometrical isomerism is possible around the double bond. However each carbon atom of other double bond has two different atoms/groups and hence geometrical isomerism is possible around this double bond. Hence, only two geometrical isomers are possible.