Let $A\in \mathrm{Mat}_{5\times 4}(\mathbb R)$ be such that the space of all solutions of the linear system $AX^t=[1,2,3,4,5]^t$ is given by $\left\{[1+2s,2+3s,3+4s,4+5s]:s\in \mathbb R\right\}$. I need to find $\mathrm{Rank}(A)$.
I don't know where to start. I need some hints.