A $50mm300mm($finish dimensions$)$ tim. ber plank is used as a diving board. The diving board is held down at end $A$ by a steel strap that is secured by anchor bolts, and it rests on a roller at section $B.$ Calculate the maximum permissible load, $P_{\text{m}\text{a}\text{x}\text{d}},$ that can be exerted on the beam by a diver if the allowable fiexural stress in the wood is ${}_{\text{a}\text{l}\text{o}\text{m}}=11$MPa and allowable shear stress is ${}_{\text{t}\text{o}\text{w}}=120$ kPa.