In a family, the father took 1/4 of the cake and he had 3 times as much as each of the other members had. The total number of family members is

Let there be (x + I) members. Then, Father's share $=\frac{1}{4}$ share of each other member $\begin{array}{l}=\frac{3}{4x}\\ \therefore 3\left(\frac{3}{4x}\right)=\frac{1}{4}\iff 4x=36\iff x=9\end{array}$

Hence, total number of family member= 10.