From a supply of identical capacitors rated $8\mathrm{\mu F},250\mathrm{V}$ the minimum number of capacitors required to form a composite $16\mathrm{\mu F},1000\mathrm{V}$ is _______

In each row four capacitors, are present then effective capacity is $2\mathrm{\mu F}$  and voltage is 1000 V. Eight  such rows are in parallel connection. Final equivalent capacity of the combination is $8\times 2\mathrm{\mu F}=16\mathrm{\mu F}$ and Voltage is 1000 V. 

$\therefore \text{ Total no. of capacitors are }8\times 4=32$