The time taken by a block of mass m to slide down from the highest point to the lowest point on a rough inclined plane is 50 % more compared to the…

The time taken by a block of mass $\displaystyle m$ to slide down from the highest point to the lowest point on a rough inclined plane is $\displaystyle 50 \%$ more compared to the time taken by the same block on identical inclined smooth plane. Both inclined planes are at $\displaystyle 45^{\circ}$ with the horizontal. The coefficient of kinetic friction between the rough inclined surface and block is $\displaystyle \_\_\_\_$.