Suppose a bipartite graph with two parts $A, B$, for every ${b \in B}$$b \in B$ we know $deg(b) \ge 1$$\deg(b) \ge 1$.
Prove there exists an adjacent $a \in A, b \in B$ such that $\frac{deg(a)}{deg(b)} \ge \frac{|B|}{|A|}$$\frac{\deg(a)}{\deg(b)} \ge \frac{|B|}{|A|}$.