Answer
$f=\dfrac{AB(p+1)}{24}$
Work Step by Step
Multiply $B(p+1)$ to both sides of the equation to obtain:
$$\require{cancel}
\\A(B(p+1))=\dfrac{24f}{B(p+1)} \cdot B(p+1)
\\\\AB(p+1)=\dfrac{24f}{\cancel{B(p+1)}} \cdot \cancel{B(p+1)}
\\AB(p+1)=24f$$
Divide $24$ to both sides to obtain:
$$\dfrac{AB(p+1)}{24}=\dfrac{24f}{24}
\\\dfrac{AB(p+1)}{24}=f$$