$1\mathrm{.}30$ The lap joint is connected by three $20-$mm$-$diameter rivets. Assuming that the

axial load $P=50kN$ is distributed equally among the three rivets, find $($c$)$ the maximum average tensile stress in each plate.

At $($c$),$ on what basis can we use this equation?

maximum tensile stress$=$ P$/($b$-$d$)*$t