$-h=-\frac{1}{2} g t^2$  ($1^{\text {st }} \text { ball }$)

$\Rightarrow 122.5=\frac{1}{2} \times 9.8 t^2$

$\Rightarrow t^2=25 \Rightarrow t=5 \,s$

Another ball is dropped after $2$ second so it took only $(5-2)=3 s$

$-122.5=-u(3)-\frac{1}{2} \times 9.8 \times 3^2$

$\Rightarrow 122.5=3 u+4.9 \times 9$

$\Rightarrow 3 u=78.4$

$\Rightarrow u=26.1 \,s$