3-ethyl -2-Pentene(X) under go reaction with $Hg{\left(OAc\right)}_2/H_{2}O$  followed by $NaB{H}_4$ gives product (Y); but when (X) is reacted with $B{r}_2/H_{2}O$gives product (Z) and (X) with $HBr/H_2{O}_2$  gives product (P).