Fig. P$3.24$

$3\mathrm{.}25$ A $30-lb$ vertical force P is applied at $A$ to the bracket shown, which is

held by screws at $B$ and $C.($a$)$ Replace P by an equivalent force$-$couple system at

B$.($b$)$Find the two horizuntal forees at $B$ and C which are equivalent to the

couple obtained in part a$.$